I have a Simaudio Moon 110LP phone preamp amplifying a Dynavector 20X2L cartridge on a VPI Classic. It feeds in to an Outlaw Audio RR2160 amp which drives Magnepan LRS speakers.
I recently moved and two months in I realized my speaker placement wasn’t quite right, so today I reorganized my listening room. This involved unplugging some power cables but I kept most of the interconnects in place. I did have to disconnect the phone stage from the amplifier.
After getting things back into place, I listened to some music using coaxial input before reconnecting the interconnects of the phono stage. When I tried to, I actually got some electric current that burned my hand slightly. This came from the back of the amplifier. I made sure everything was unplugged and tried again - this time a spark and smoke from the interconnect making contact to the back of the amplifier.
I’m so confused why this would happen, but eventually I did get everything connected. Now the output from the phono stage is just a bump every 1 second. It doesn’t amplify the signal from the TT.
My amplifier has a built in phono stage and using this I was able to verify that the turntable is still producing a signal. The built in phono stage sounds terrible, however, as thin and flat as paper. It is music, however.
When I connect the phono stage to the power, the blue light on the front illuminates for a moment and then goes dark.
Incredibly, when I was unplugging the phono preamp, I actually got some current from simply touching the exterior of the box. Something is seriously wrong and dangerous with my setup, and this box was grounded to the turntable with a ground cable, which was connected to the outlet with a three prong cable with ground.
Has anyone experienced anything like this before? I will email Simaudio and see if they’ll repair it. I’m also taking recommendations for replacements. I liked the 110LP and maybe will just replace with the 110LPV2.
Note... Inside heavy light gray line is me. Outside heavy light gray line is you.
Saturday, check for voltage from the outer shell of the output RCA jack of the phono preamp to the outer shell of the analog input RCA jack on the RR2160 amp.
Should of done that to begin with...
Both units powered on.
5.5Vac on V
0.02Vac on LoZ
My response:
Could you check again using the DC setting.
LoZ is not needed for either AC or DC in this case.
Question:
I didn't think about until just now. Was all associated audio equipment still plugged into the same 120Vac outlets? Especially the CDP? It doesn't need to be turned on, just plugged into the wall outlet. At present the CDP is the only piece of equipment the uses an EGC that is connected to the RR2160 amp with ICs.
Need to have everything connected the same way as the day you received an electrical shock and the spark event.
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jea48
When you get a chance check the wall outlets the equipment plugs into for proper Hot / Neutral polarity and for equipment ground. At least you will be able to check them off your list.
You
I sent a lot of messages last night so perhaps you missed:
You
I tested the outlets where things were plugged in. The hot/neutral is reversed. So the hot is the longer left slot, the neutral is the shorter slot on the right. The ground appears to be functioning.
My response:
Larger of the two slots is the neutral side of the receptacle. You measured 120Vac to EGC ground. (Hot black ungrounded conductor is connected to neutral terminal)
Smaller slot is the Hot side of the receptacle. You measured zero nominal volts to EGC ground. The white color "Grounded Conductor", "White neutral conductor", is connected to the Hot terminal of the receptacle.
Yes, the branch circuit wiring, Hot and neutral conductors are reversed (wire wrong) on the duplex outlet.
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You
Explicitly, this means when I’m on V or LoZ and I go into hot/neutral I get 120Vac. When I go neutral/ground I get close to zero, and when I go neutral/hot I get ~120Vac. However, hot/neutral is reversed.
????
You're starting to sound like me late last night...
However, hot/neutral is reversed.
On that I agree.
i don’t think it matters but when I plug one lead of MM into ECG and the other isn’t connected to anything I get 5V on V but it disappears of course on LoZ.
Well.... Though the Audio system equipment probably has been in use, operating Ok plugged into wall outlets with the Hot and neutral branch circuit conductors reversed, wired wrong, For now I think we can over look it. But with that said it needs to be corrected.
Question... Are you renting or do you own the residence? Is the electrical panel located in the dwelling? Are the wall outlets on opposite sides of the room on the same breaker in the electrical panel. Roughly how old would you say the building, electrical wiring might be?
I realize the electrical wiring issue is off tract at the present. At some point, after we figure out the problem with your audio system we will come back to it.
his wouldn’t be a big deal if the three other RCA inputs still worked. Last weekend I connected the preamp to analog input 4 on the amp and it made the same soft bump sound. I just remembered the blue sound node also has an integrated DAC and RCA out. So if I don’t mind risking frying it I could try connecting it. Ideally I should find something cheaper, maybe my TV (which is old and I don’t use). I’ll check if it has RCA out when I get home.
Before you do anything run a quick test on the RR2160 amp. Need everything associated with the audio system plugged into the120V wall outlets as they were the day of the spark event. Need all ICs connected, except the ICs of the phono preamp, to the RR2160 amp.
Test:
I want you to measure from an analog RCA jack input (that you have not connected the phono preamp to) outer signal ground shell to the wall outlet EGC.
Problem may be you can't unplug any audio equipment from a wall outlet to use the power cord for a test lead extension. You could use a 3 wire grounding type drop cord and use the EGC from it. Just make sure the wall outlet you use has an EGC. You know how to test for that.
If it's easier for you can plug an IC into the RCA jack on the RR2160 amp and touch the mm test lead probe to outer shell of it.
Set the mm to V ac .
For the heck of it after measuring from the input signal ground of that jack to EGC ground, repeat the test on the the analog input jack signal ground you oroginally had the phono preamp ICs plugged into. The day of the electrical shock, spark event.
On the good power cords, the ground connection (round pin of plug) is longer than the flat pins....that means the unit is grounded until the last little bit of plug is removed from the wall.
I just plugged everything into all the outlets as it was last weekend (minus the interconnects between phono and amp) and re-did the test where one lead is on preamp output, one on amp analog 1 input rca plug.
121Vac on V
68.9Vac on LoZ
0Vdc on V
isnt that it? 69Vac on LoZ is a major issue, right?
I then unplugged the grounded 3 prong power cord from the cd player and the voltage registers ~0Vac on LoZ between the RCA output on the preamp and the rca input on the amp.
both amp and preamp were on at that time.
i then turned the amp off and turned off its power switch but left it connected to the wall and the same readings were registered.
if this is the problem I think it is, I need your help to understand what the core source of the problem is and what piece of equipment is misbehaving.
i unplug the preamp from power. I unplug all interconnects from preamp. I leave the grounding wire connected, which grounds the preamp to the record player tone arm. I put one lead of the multimeter in the ECG coming from the outlet where the preamp, amp, and CDP are connected, and the other lead on the RCA output of the preamp and I read 121Vac on LoZ.
I now unplug the (grounded) power cord from the turntable and do the same test (still with the ground cable attached to the preamp and the tone arm) and see 0Vac.
note: The turntable is connected to a different power outlet than the preamp and the amplifier. the turntable is off the whole time.
the building I’m in, yes it’s old (I think maybe 100 years) and I rent. I will need to test the outlets where the TT is plugged in tomorrow.
i unplug the preamp from power. [ME (Dead NO power)]
I unplug all interconnects from preamp.
I leave the grounding wire connected, which grounds the preamp to the record player tone arm.
I put one lead of the multimeter in the EGC coming from the outlet where the preamp, amp, and CDP are connected,
and the other lead on the RCA output of the preamp
and I read 121Vac on LoZ.
I now unplug the (grounded) power cord from the turntable
and do the same test (still with the ground cable attached to the preamp and the tone arm) and see 0Vac.
/ / / / / / /
My response:
Sounds to me the difference of potential, voltage, of 121Vac is coming from the TT 120V power section that feeds power for the motor.
121Vac fault circuit path through the mm volt meter.
121Vac Hot conductor from wall outlet to >>> TT motor section to >>> tone arm ground to >>> ground wire to >>> phono preamp ground lug, metal enclosure of preamp, signal ground (outer shell) RCA jack to >>> test probe lead of muli-meter >> through volt meter >> out test lead probe wire to >>> EGC of wall outlet.
The two points for the voltage,
(1) the Hot conductor at the wall outlet that feeds the TT
* (There has to be problem in the 120V section of the TT. Will need to check that out)
(2) The EGC at the wall outlet that feeds the CDP and unplugged phono preamp
Your job now is to verify there is continuity from the 120Vac Hot prong on the TT IEC inlet connector and the tone arm ground. That just don’t seem possible...
You get to try out the continuity setting on the mm.
For this there can’t be any LIVE voltage at the points you will measure for continuity.
Leave TT unplugged.
Test:
Power Switch on TT must be Switched ON...
First set mm to V
Measure for voltage from the tone arm ground lug to one of two line prongs. I don’t know which one is the actual Hot prong so you will measure from both.
You should measure zero volts from each one (on the IEC) to the tone arm ground lug.
No voltage... Correct?
Next move the switch on the mm clockwise one setting. That should be the continuity setting.
Touch both metal probes to one another.The meter should make an audible sound. You probably will see something displayed on screen as well. (It will in the mm instruction manual.)
Next, touch one mm probe to the arm ground lug and the other probe to each of the outer prongs on the IEC inlet connector.
May may not hear the audible sound, look at the mm display. It may show a low resistance measurement.
I forgot to mention in my above post that the EGC for the TT has to be open, broken, somewhere. It could be at the wall outlet the TT is plugged into or it could be open, broken, at the other side of the TT IEC EGC ground prong inside the TT, or the point the ground wire connects to the TT itself...
Because you don’t know where it is open, broken, DON’T plug the TT grounded power cord into any other wall outlet to find out. You could really cause electrical damage to the TT 120V electrical wiring system.
If you haven’t started the continuity test I wrote in my above post there is quicker way test if the Hot conductor is faulted somehow to the tone arm ground.
Disconnect the tone arm ground wire from the phono preanp ground lug.
Plug in the TT power cord into the same wall out you had it plugged into last night.
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Set mm to V (volts).
Measure for voltage from the EGC wall outlet you used yesterday to the tone arm ground. you should measure 121Vac.
This conversation is going a little nuts. Testing with multiple devices for this is nonsense, except maybe as a learning exercise for new techs.
You should let a tech do all of this instead but if you must, wear insulated shoes and avoid any other points of contact after the device is plugged into the wall. Touch the device ONLY with your meter. Same for the EGC. If you are holding the EGC when you touch an active AC voltage you can be electrocuted. Set up your test area so that you can reach everything, and the EGC is readily accessible for your probe before you plug anything in. If you are squirming and contorting to connect your meter you are likely to make mistakes. Use alligator leads so you can leave the ground attached without moving it.
Plug in one piece of gear at a time, connecting nothing but the power cord. Measure voltage to the EGC using LoZ. Do this from the chassis to EGC and the outer ring of the RCA connectors to the EGC. You should measure practically zero.
If you find a high voltage use a cheater plug and measure the CURRENT from the same points to the EGC. Again, current should be nearly zero, but small leakages around 10 mA are OK. This will tell you the magnitude of the short. I suspect you have a relatively high voltage with medium current (2A or so).
Please note that using a cheater plug is dangerous as it may elevate the chassis voltage. Take extra care after attaching it.
If none of these yield answers, check the voltage on the INSIDE of the RCA. Take care as it may be high especially with tube gear. It’s worth sacrificing a cheap RCA cable to do this easilly. Cut an end off and expose the inner wire for your probe.
If you suspect a tube pre/amp, you may have DC on the inner wire. That's bad too, but also will need you to select DC on your meter.
This conversation is going a little nuts. Testing with multiple devices for this is nonsense, except maybe as a learning exercise for new techs.
. What a bunch of BS.
But yet the OP has found the problem. It appears to be the TT. We will know for sure when he posts back. For a layman, Imo, @obarrettdid a pretty good job.
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Just curious, what are your hands on electrical troubleshooting qualifications experience?
Look folks, it's simple. Watch me say it in five easy steps.
1. Disconnect all components, from the wall and from each other.
2. Test each component for internal shorts using the continuity feature of your DMM. This is completely safe, and you can't damage any component any more than it already is.
3. If no shorts are found, take your components to a tech for further diagnosis.
4. If a short is found, take shorted / faulty component to a tech for repair.
There is continuity from the ground prong of the TT to the tone arm ground lug. No continuity from either of the other two prongs of the TT.
I attached one three prong power cord to the outlet where the amp/preamp/CDP are connected and then the other to the outlet where the TT is plugged in. I turned mm to V/LoZ, attached one lead to the ground of one, the other to the ground of the other. 120Vac.
so the issue is clear: there is a 120V difference between the grounds of the two outlets, which explains every measurement I’ve made as well as explaining the spark event I observed.
doesnt this mean one of these grounds is hot? If so that seems super dangerous. I’m not entirely sure how to check which one is messed up, but this is probably related to the issue of reversed polarity I observed when testing the outlets where the amp is connected to. Maybe the polarity isn’t reversed, just the ground is hot. But when I put one lead of the probe into the ground there and the other on a piece of metal which is unplugged from anything, I see only 5V on the MM.
@devinplombieri don’t understand your criticism. The issue I just diagnosed wouldn’t be caught by your five-step recipe. The eventual issue is to me quite surprising but I’m not an electrician and I don’t know how common such an issue is.
I still don’t even understand what it means that the grounds of the two different outlets have a 120Vac difference.
thanks, Jim, for all your help. Without it, I wouldn’t have caught this issue, I would have bought a new preamp and I would’ve fried that one too.
It’s most likely a major issue with your meter. A good meter should accurately measure a hard voltage in either standard or LoZ modes.
"It’s most likely a major issue with your meter. A good meter should accurately measure a hard voltage in either standard or LoZ modes."
No, it’s not a problem with the brand-new multi-meter.
"isn’t that it? 69Vac on LoZ is a major issue, right?"
First a digital voltmeter with a LoZ circuit meter setting incorporates a load across voltmeter circuitry. That pretty much eliminates phantom, ghost, false, AC voltage measurements. I believe I read in the manual for the Klein multi-meter, (the OP bought), the load resistance is 3K ohms.
There is a great example of how it works. The unloaded voltage reading measured 121Vac (Using the V setting on the multi-meter.)
The LoZ measurement of 68.9Vac reading indicates there in not a Bolted Hot ground fault. Bolted? A solid Hot to ground electrical fault. The LoZ 68.9VAC tell me the is a VD, (Voltage Drop), in the Hot to ground fault. Exactly what is causing VD, series resistance, I have no idea. I just know from @obarrett posted his voltage measurements it is not a Bolted Hot to ground fault.
FWIW, for troubleshooting lose or open electrical wiring circuits in the electrical field a regular multi-meter is worthless, unless it has a LoZ setting.
A regular digital voltmeter internal resistance is in the megohms.
Do you still measure 120V between your two grounds when your DMM is set to standard AC voltage mode?
Yes I measure 120Vac across the grounds of the two outlets in V AC mode on the MM. well, to be clear, both outlets have 2-to-6 outlet converters sitting on top of them and I’ve connected a three prong power cord to each. So there are other things to check.
There is continuity from the ground prong of the TT to the tone arm ground lug. No continuity from either of the other two prongs of the TT.
OK
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I attached one three prong power cord to the outlet where the amp/preamp/CDP are connected and then the other to the outlet where the TT is plugged in. I turned mm to V/LoZ, attached one lead to the ground of one, the other to the ground of the other. 120Vac.
IF true that indicates the wall outlet the TT is plugged into has a Hot equipment ground contact at the receptacle. (At this point there is not an internal Hot fault in the TT)
Before I go any farther... Test the receptacle as you have the others for the correct AC hot and neutral connections polarity on the receptacle outlet and from the Hot to the equipment ground contact. EDIT. Use both the V and LoZ mm settings.
Is the Electrical panel for your outlets in your apartment? If not do you have access to where it is located?
I haven’t yet had the chance to do the tests you suggested in your last post @jea48
I just want to mention that @jea48’s advice, contrary to the statements of @erik_squiresand @devinplombier, has been essential to understanding what’s going on. I’m inexperienced so I make many mistakes and my messages have been confusing at times, but I don’t see the need to come in to this thread and criticize @jea48for providing the only instructions that have advanced my understanding of what is a dangerous situation.
regardding LoZ on my MM: without this I’d be thinking that the SMPS has 48Vac on the sleeve which is what the reading was on V and which is factually false.
I'm not sure preforming the same test for checking the wall outlet the TT plugs into for reversed Hot / neutral wiring connection to the duplex receptacle outlet and to check for the presence of an EGC will work in this situation. Don't see a receptacle Hot equipment very often.
I've looked at different scenarios for how the equipment ground could be Hot to a known EGC ground and the test with the mm would be flawed.
The most common instance is when an equipment ground is not present at the outlet box. Therein a two-wire branch circuit wiring. A homeowner replaces a two-wire duplex receptacle with a three-wire grounding type duplex receptacle. He wants a ground, so he installs a jumper wire from the neutral terminal on the receptacle and connects it to the safety equipment ground terminal. Called a Bootleg ground. Very Dangerous! It doesn't matter if a plug-in circuit tester is used, or a digital multi-meter is used it will show the presence of a ground.
One danger with a Bootleg ground is if the Hot and neutral conductors are reversed on the duplex receptacle. That's not good... The ground contact of the outlet will be HOT!
Is that what you have? Maybe, maybe not. You measured two different voltages in an earlier post. On V 121Vac and 68.9Vac on the LoZ setting. For that to happen with a bootleg ground there would have to be a poor and or corroded connection. The high megohm internal circuit of the mm V setting won't add any load to across the high megohm Voltmeter Like the LoZ setting will. Could that be the case. Maybe. But the only true way would be to pull the outlet out of the box aways for a look.
I cannot advise you to do so.
First, you are not the owner of the building.
Second, the breaker feeding the outlet would have to be turn off. And verified 100% it is dead.
Third, and very important reason you said the building is old. Hard telling what type insulation covering was used on the branch circuit wiring. If really old wiring it could rubber and cloth insulation. That stuff gets old the rubber gets really hard and brittle. It doesn't like to be disturbed.
It's time to call building Maintenace. A hot safety ground is definitely electrically dangerous. A reversed hot and neutral on an outlet is also electrically dangerous.
I believe I have a way to check the duplex receptacle outlet the TT is plugged into.
I'll post it later.
For now, hopefully for the last test, the solution would be to use another EGC grounded outlet. Like the subwoofer receptacle. I don't want you to use the CDP receptacle though, for the test. The CDP, I believe, because it uses the EGC is grounding all the non EGC equipment. It was providing the return path for hot to EGC faulted circuit.
The properly EGC grounded TT, (Which I don't think is right), will do the same.
(FWIW I doubt the CDP signal ground is directly connect to the EGC grounded CDP chassis. Just a guess the signal ground is in series with around a 10ohm resistor. This helps prevent ground loops, hum.
As for the TT EGC connected to the tone arm, I would contact the VPI support on that. That makes no sense to me.
I've looked at different scenarios for how the equipment ground could be Hot to a known EGC ground and the test with the mm would be flawed.
The most common instance is when an equipment ground is not present at the outlet box. Therein a two-wire branch circuit wiring. A homeowner replaces a two-wire duplex receptacle with a three-wire grounding type duplex receptacle. He wants a ground, so he installs a jumper wire from the neutral terminal on the receptacle and connects it to the safety equipment ground terminal. Called a Bootleg ground. Very Dangerous! It doesn't matter if a plug-in circuit tester is used, or a digital multi-meter is used it will show the presence of a ground.
One danger with a Bootleg ground is if the Hot and neutral conductors are reversed on the duplex receptacle. That's not good... The ground contact of the outlet will be HOT!
Bootleg ground and reverse polarity, isn't that exactly what I said?
I made the following measurements, both on V and LoZ. All the measurements were identical on both settings. I made the measurements two times: once with the 2-to-6 outlet converters on, and once with them off (accessing the bare outlets). The 2-to-6 converters made no difference in the measurements. So I make no distinction between V/LoZ or converter on or off in the below.
Let R denote the (shorter) female slot, L denote the (longer) female slot, G denote the ECG which sits below in the middle.
Outlet 1 (amp, preamp, CDP):
RL: 120Vac
LG: 120Vac
RG: 0.09Vac
Outlet 2 (TT, subwoofer):
RL: 120Vac
LG: 0.36Vac
RG: 120Vac
Now I took a 3-prong power cord, first from the CDP, next from the TT, and plugged into Outlet 1. I used two different cords to ensure one of the cords isn’t the problem. I plugged one MM lead into the ground of the other end of the power cord, and the other lead into the ECG of Outlet 2, and registered 120Vac on V and LoZ.
There is a third outlet where no equipment is attached. It’s on the same wall as Outlet 2. It’s measurements are the same as Outlet 2 and it also has 120Vac between its ground and the ground of Outlet 1.
I am not really following from the recent messages if there are additional tests I should run. It seems like next I should call a professional electrician.
From reading about reverse-polarity bootleg ground, it seems too lethal to be the source of the issue. I should consult with a professional either way though.
It seems like next I should call a professional electrician.
I should consult with a professional either way though.
I agree.
You should call the building manager or Landlord. They more than likely have their own Electrical Contractor they use for the electrical work in their buildings. You shouldn’t have to pay anything. Some of the electrical is unsafe.
FYI, I would remove the 2 to 6 outlet "converters" for the day Electrician is scheduled to come out.
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As for the measurements in your above post.
Outlet 2 (TT, subwoofer):
RL: 120Vac
LG: 0.36Vac
RG: 120Vac
The Hot / neutral polarity wiring is correct.
Hot (small slot) to ground 120Vac is correct.
Neutral to ground 0.36Vac looks good.
If it were me, I would buy one, or two if needed, descent plug strips and plug all your audio equipment into it/them plugged into this wall outlet. At least until you can get an electrician to troubleshoot and fix the electrical wiring problems.
/ / / /
Outlet 1 (amp, preamp, CDP):
RL: 120Vac
LG: 120Vac
RG: 0.09Vac
This outlet has the Hot and neutral reversed, mis wired.
Therefore LG: 120Vac Is wrong, not safe.
I would not use this outlet to feed your audio system equipment. To be honest, I can’t see how you can...
Imo, outlet 1 ground is screwed up causing the 120Vac between outlet "1" and outlet "2" equipment grounds. The wire feeding the ground contact on the outlet is actually the branch circuit HOT ungrounded conductor. It’s not a ground conductor. Good chance the branch circuit is only a 2-wire circuit for Outlet "1".
If you have a drop cord to plug into another grounded outlet, that tested correctly for Hot / neutral wiring polarity, you could confirm if it is the cause of the 120Vac measurement.
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/ / / / /
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I was about to send this post when I noticed your latest post.
Looking for info on the VPI Classic TT I found this YouTube video.
Note the steel plate. Apparently, the tone arm tower base is bolted to the steel grounded plate. ??? I don’t have any proof it is though. Fact, you measured continuity between the IEC inlet connector EGC and the tone arm ground lug/ ground wire.
Here is another possible example for the ground contact on the wall outlet, the TT has been plugged into,... to be Hot 120V.
Assuming everything was fine with the audio system until you decided you wanted to tweak the speaker placements.
IF by chance you unplugged the TT power cord from the wall outlet. (Or for any other reason the outlet could have been disturbed using it for other things plugged into it.)
Assuming the duplex receptacle was not grounded. (Therein two-wire branch circuit wiring. Old worn out 2 wire outlet was changed out to new 3 wire grounding outlet by a former tenant.
No wire is connected to the EGC ground terminal
Outlet opening is 1 gang flush rough-in steel switch box.
Hot and neutral are revered on the outlet. Therein the Hot conductor is connected to the neutral side terminal on the outlet. Neutral conductor is connected to the hot contact terminal screw side.
On a regular grounding type duplex receptacle, the EGC contact terminal screw is on the same side as the neutral contact terminal screw.
It is possible the duplex receptacle was not tightly fastened to the wall recessed rough-in box. Odds are it is not.
It is possible if the outlet was disturbed by, Unplugging the power cord and or plugging the cord into the outlet, the HOT neutral contact terminal side and the EGC ground terminal is now contacting the side of the steel 1 gang box. The side of the steel box is electrically energizing the ground contacts of the duplex receptacle.
This one you could safely check.
Remove the outlet plastic plate.
Once removed look at the neutral contact side of the outlet. Does it look like it is against the side of the steel box?
If yes, do you a plastic tea or milk container you can cut out a rectangular piece of the plastic? Slide it between the outlet and the steel box. You can cut a rectangular piece for the other as well.
Slightly tighten the two 6/32 screws that fasten the outlet to the box if needed.
Replace wall outlet cover.
Check the ground contact to see if it is still hot.
No need to reply to either post, unless want to..
If you have any further questions, you can always PM me using the Audiogon messaging system.
Hey Jim, the reason why I didn’t have an issue before is that I wasn’t using outlet 2 before. Everything that needed a ground was in outlet 1. Only after I moved things around could I access outlet 2.
thanks again to you. Thanks also to you Devin. If I actually have a reverse polarity bootleg ground I will be so angry. You guys saved me more than money.
Reverse polarity OR bootleg ground alone won't manifest until something else goes wrong. It's the combination of the two that is potentially lethal, because any grounded (3-prong cord) piece of equipment you plug into such an outlet sees its chassis, cover (and anyone who touches it) energized.
Please do post your electrician's findings. Curious now!
Hey Jim, the reason why I didn’t have an issue before is that I wasn’t using outlet 2 before.Everything that needed a ground was in outlet 1. Only after I moved things around could I access outlet 2.
FYI, outlet 2 has an earthed ground. Well, the mm measurement says so. A plug in circuit tester would say so. A Bolted Hot to the EGC ground fault might tell a different story.
Using outlet 1 you didn’t/don’t have a ground. The ground contact on the outlet is HOT 120Vac with reference to an earthed ground. All the metal enclosures of the audio equipment were HOT 120Vac referenced to ground. Even audio equipment that didn’t use an earthed EGC.
The TT power cord is a 3 wire cord. When plugged into outlet 1 it fed the branch circuit HOT 120Vac to the TT IEC inlet connector EGC prong. That in turn fed HOT 120Vac to metal parts of the TT and to the tone arm ground, *(by the way the tone arm was HOT with reference to an earthed ground), to >> the phono preamp enclosure, which made all the RCA jacks outer ground shells HOT 120Vac that contaminated all the other metal enclosures through the interconnect cables signal ground conductor.
Why you never got an electrical shock or had problems with your audio system equipment? There was not an earthed ground introduced into the equation.
So, for the same reason a bird perched on a high voltage power Line doesn’t get shocked.
Now the Squirrel is a different story. He will jump onto High voltage power Line and run down the Line without a care in the world. It’s his dismount from the high voltage power Line to the top of the metal earth grounded pole transformer is his fatal problem. If only he had jumped instead of stepped.
FYI, I am pretty sure the heat radiator shown in the video is earthed grounded. Had you been able to touch it with one hand, (in the summer months), and touched any of the HOT 120Vac metal enclosures of the audio equipment with the other hand there is a chance you would have been electrocuted. Therein dead.
DO NOT use outlet 1, until it is wired correctly by an electrician.
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I suggest you try another test. Plug an OEM power cord into outlet 1. Insert one of the test lead probes into the IEC female ground contact.
Turn mm to V and touch the other test lead probe to a bared (unpainted) metal place on the heat radiator. You can also use the LoZ setting on the mm as well.
@jea48, I tried to follow this thread but it became too complex for me to understand what was happening, so I apologize if this question was asked and answered and I missed it.
Bootleg grounds: now I understand what they are and the reason someone might wire an outlet with a jumper from neutral to ground in order to put a (3 hole) grounding receptacle on a (2 hole) ungrounded circuit to make it pass the test with a real basic EZ CHECK circuit tester. Since my house was built in early 1960s and has (2 hole) ungrounded outlets in the back of the house and (3 hole) grounding outlets in the front, although the grounding outlets all pass the EZ CHECK circuit tester, it still seems like my house might be a candidate for those grounding outlets to be bootlegs.
I went to google to look for a simple answer of what to look for with an AC VM to identify bootlegged and normal outlets and got drastically conflicting results from AI.
Again, I apologize if you previously covered this, but is there a way to verify with an AC VM whether a 3 hole outlet has been bootlegged or not? I compared an outlet on a circuit that I installed myself that I KNOW is NOT bootlegged, and ground to neutral reads 0.105; then on a 3 hole outlet that was there when I bought the house and it reads 0.25. (My meter does not have an LoZ setting.)
Do those readings mean anything, or is the only way to know for sure to remove the older grounding outlets and visually inspect them for jumpers from neutral to ground? I am getting the impression that there are more expensive meters that will verify whether or not a bootleg ground was used?
Thank you, and again, my apologies if I am asking a redundant question on this thread.
Here is a photo of a two wire old rubber cloth covered conductors Bootleg grounded outlet . The wiring is really old. pre-Thermoplastic, PVC, insulated wire. PVC Thermoplastic insulation is really old too. THHN/THWN replaced it, going from memory, in the early 1970s.
Here is good video on Bootleg ground wired outlets. (FYI, a bootleg ground is a NEC code violation. Alwas has been)
How many wall outlets are there in the old part of the house?
The only 100% sure way to check the outlet is look for the jumper wire. Remove the wall outlet cover plate. Good chance using a high power LED small diameter flashlight with the lighting in the room subdued you should be able to see the jumper on ground terminal side of the duplex receptacle outlet without pulling the outlet out of the wall box. (Turn off the circuit breaker at the panel if you are going to do any poking around.
Another sure way is plug in a high current load into the outlet like a hair dryer or portable vacuum cleaner. Anything that draws enough current on the branch circuit wiring to cause a voltage drop on the wiring.
First measure for AC voltage from neutral contact, (longer straight slot of the two.) Notate the small voltage reading.
Next plug in and switch on the load. Check the voltage again from the neutral contact to the ground contact on the outlet. If the outlet is bootleg ground wired the reading will be the as the first measurement. If the measured voltage is a few to several volts lower, it is not a bootleg ground.
@obarrett I appreciate this educational thread and hopefully it's okay with you if I piggyback on it just a bit more.
@jea48, you asked how many 2 hole outlets I had in the back of the house, and there are 3 per bedroom making a total of 9.
BUT: I removed two of my "grounded" 3 hole outlets to inspect them for a bootleg ground. The two I removed do NOT have a jumper from a neutral (white) screw to the green ground screw, but they also do not have any ground wire connected to the green ground screw. In other words, the only wires connected to those two outlets are the black wire and the white wire. But the cheap EZ check tool says that they are correct??? With the breaker tripped and the outlet connected to both wires, I tested for continuity between the white screw with white wire and the green ground screw with NO wire and I have continuity???? Are they somehow bootlegged from inside the outlet?
Thank you for taking all of the time that you do to provide education and assistance to those of us who have a rudimentary grasp, or probably even less in my case, and struggle with the subject. I certainly appreciate all your help over the few years I have been on A'gon.
But the cheap EZ check tool says that they are correct??? With the breaker tripped and the outlet connected to both wires, I tested for continuity between the white screw with white wire and the green ground screw with NO wire and I have continuity???? Are they somehow bootlegged from inside the outlet?
I assume the 3 wire duplex receptacle was fastened to a steel rough-in box when you used the "EZ check tool", (and with the circuit dead), you checked for continuity from the neutral contact to the green ground screw.
That indicates the steel box is grounded. If the branch circuit wiring that was installed many years ago is only 2 wire that means a ground wire was installed at a later date. I would say, to replace a two wire outlet with a 3 wire grounding type outlet.
Many many, many NEC code edition cycles ago NEC allowed a ground wire could be installed from a steel outlet box to a metallic cold water pipe using an approved pipe clamp. For years a duplex receptacle was considered grounded when fastened to a steel grounded box. My guess that is what you have.
The duplex receptacle that is installed on the grounded steel rough-in box may now be an auto ground type receptacle. (One end of the Yoke of the outlet has a stainless steel clip that puts pressure on the 6/32 machine that bonds the supporting back strap to the grounded steel box.
Years ago before the auto ground clip NEC considered the outlet was effectively grounded to the box with just the two 6/32 screws.
I assume the 3 wire duplex receptacle was fastened to a steel rough-in box when you used the "EZ check tool", (and with the circuit dead), you checked for continuity from the neutral contact to the green ground screw.
You are a genius, @jea48! Thank you much for getting back to me on this!! To check for continuity from the white screw/white wire to the ground screw I remembered I had the outlet pulled out a bit from the steel box, so I just now did the same thing, and I must have had the screw lightly touching the box the first time. This time, with the breaker tripped, I made sure the outlet and hardware was completely clear of the box and, voila, NO continuity. Then I let the screw touch lightly, and presto--continuity. So I set it up so I had no continuity, put the EZ Check back in, flipped the breaker back to ’ON’, and the EZ check read as it should--"open ground."
That indicates the steel box is grounded. If the branch circuit wiring that was installed many years ago is only 2 wire that means a ground wire was installed at a later date. I would say, to replace a two wire outlet with a 3 wire grounding type outlet.
Many many, many NEC code edition cycles ago NEC allowed a ground wire could be installed from a steel outlet box to a metallic cold water pipe using an approved pipe clamp. For years a duplex receptacle was considered grounded when fastened to a steel grounded box. My guess that is what you have.
How kosher is this set up that I have?
Oh, and on edit: I have three duplex outlets for circuits I put in myself right next to the duplex that I just checked. With all the outlets installed and breakers tripped, I do measure continuity from an equipment ground hole of the duplex in question to an equipment ground hole of the duplex outlets I put in myself. Since I know for a fact that the duplexes I put in were wired correctly (from duplex back to the panel, black/white/ground) doesn’t this mean that ground for the steel box of the duplex in question must end up back at neutral/ground bar at the main panel?
I put in were wired correctly (from duplex back to the panel, black/white/ground) doesn’t this mean that ground for the steel box of the duplex in question must end up back at neutral/ground bar at the main panel?
Several NEC code cycles ago NEC was changed stating branch circuit conductors shall be installed in the same raceway or cable assembly. That includes the EGC. (Equipment Grounding Conductor).
When a steel box is used the EGC shall be bonded to the box. Per NEC if the duplex receptacle is an auto grounding type a ground pigtail is not required from the EGC to the duplex receptacle. The duplex is grounded by the auto ground.
I personally still install a ground pigtail to the ground terminal screw on the duplex recept.
That’s a relief, @jea48. As long as I am not living in a potential electric chair or an incinerator I can live with it. I was going through in my mind what I was thinking I was going to have to do to run replacement circuits for replacement duplexes, and I wasn’t liking it, but time is one thing that I have enough of, so if I had some kind of bootleg set up I wasn’t understanding, I was going to get started on it.
Once again and as always, I thank you for the education.
Here is a photo of a two wire old rubber cloth covered conductors Bootleg grounded outlet . The wiring is really old. pre-Thermoplastic, PVC, insulated wire. PVC Thermoplastic insulation is really old too. THHN/THWN replaced it, going from memory, in the early 1970s.
Here is good video on Bootleg ground wired outlets. (FYI, a bootleg ground is a NEC code violation. Always has been)
I suggest you try another test. Plug an OEM power cord into outlet 1. Insert one of the test lead probes into the IEC female ground contact.
Turn mm to V and touch the other test lead probe to a bared (unpainted) metal place on the heat radiator. You can also use the LoZ setting on the mm as well.
My goodness it’s 120Vac on both settings. It is a hot ground. That’s so disturbing. Someone could easily have died and I’m surprised someone hasn’t yet.
I spoke to the landlord/my point of contact for the management company yesterday. He repeatedly told me he ‘never had any trouble with the electricity’ in my apartment until now. I don’t think I can make him understand just how serious this is.
The building super claims to be an electrician and he’s supposed to work on it tomorrow. When he opens it up I’ll have a look.
I spoke to the landlord/my point of contact for the management company yesterday. He repeatedly told me he ‘never had any trouble with the electricity’ in my apartment until now. I don’t think I can make him understand just how serious this is.
Sure you can. You can easily show him, with your multi-meter.
The ground contact is Hot 120Vac to the heat radiator.
My goodness it’s 120Vac on both settings. It is a hot ground. That’s so disturbing. Someone could easily have died and I’m surprised someone hasn’t yet.
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If you have any problem with him just mention you could have been electrocuted if you had touched the radiator with one hand and the HOT 120Vac Amplifier metal case with the other hand. electrocuted, dead.
Don’t forget to remove all of those 2 to 6 power receptacle extenders.
Yes I’m going to replace them with power strips and I’ve obviously stopped plugging anything with three prongs in there. As for the landlord, he’s sent someone to fix it, but he seems unwilling to replace the preamp. He doesn’t really seem to understand what voltage is or even what a ground is. I will try to get the super to convince him of the significance but I have little hope. I can tell him this stuff about electrocution, but he will just say that he’s ‘never had a problem.’
The deductible is too high, the v2 of the 110LP new is only $600 and renter’s insurance would give only the actual/market value of the used one I have, which is considerably less than $600.
it’s not really a problem, I’m just grateful to be alive. If I had touched the tone arm of my turntable at the same time as I was touching my CD player, I would’ve died, even if both were turned off
In your video, when you measured for voltage from the receptacle ground contact to the heat radiator the test probe connection to the receptacle ground contact was poor. The 120Vac reading was not a solid contact connection.
You should have used the OEM power cord ground. Insert the mm probe into the center ground contact. That also frees up your hand and you can focus your eyes on the probe connection to the radiator valve and the meter.
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WARNING: I hope you saved the plastic outlet cover plate you removed from the receptacle. When you remove the 2 to 6 outlet extender everything metal you see is HOT 120Vac to anything grounded. Don’t put your body between them.
** EDIT: On second thought. Don’t remove this one. Just leave it be.
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Also in case you haven’t thought of it. You are going to have to move the speakers and audio equipment out of area the electrician will be working. Take some pictures first of the equipment where it normally is sitting. Just in case he asks.
The Electrician needs a minimum of 3ft working space in front of the wall outlets. The more the better. A happy Electrician is a productive Electrician.
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