component grounding


So this whole thing about grounding audio gear. There are millions of pieces of vintage audio gear out there without ground plugs. In fact, many don't even have a polarized two prong plug. Yet search as I may, I can't find one situation where someone was killed or seriously injured from an ungrounded piece of audio equipment. I've been in the HiFi business for over 50 years.....Never saw a recall or a warning or anything until recently. This past year I built a Bob Latino ST120 Tube Dynaco clone amplifier. I was surprised to see a lampcord power cord with no ground. When I inquired I was told by many to not ground it as it wasn't necessary and might introduce hum......Can someone show me documented case where injurie resulted from an ungrounded piece of equipment?

rbertalotto

Right. Because when GFCI's came about, 50 million old homes magically had their electrical systems updated.

You would think with gfi outlets and now the entire panel in a home having gfi that the plug is no longer an issue even it was in the past. Now not to go there but I feel I must. Manufactures want to be able to sport the UL stamp of approval on their products, this will allow for them to charge customers 100 time the cost of that extra prong. We all know UL is another government tied bureaucracy and a vital part of their money laundering operations. Although adding one more prong to a plug is minimal in cost the payments to the UL are not and that grounding prong gives them cover.
Sorry to go there but as the saying goes “there are no conspiracies just as there are no coincidences”!

The new Arcam Amp I just got  (I am in th US) has a US mains style cable and plugs but the ground prong is absent, and the power socket on the amp has no ground element..

The Arcam Amp AC power wiring is certified Class II, double insulated AC power wiring.  It doesn't require an EGC.

Appliance classes - Wikipedia

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The new Arcam Amp I just got  (I am in th US) has a US mains style cable and plugs but the ground prong is absent, and the power socket on the amp has no ground element..

 

 

Hello,

As said above a lot of people float the ground. It prevents noise from ground loop hum especially on single ended equipment. Also, by having the ground plug only connected to the wall and not the component provides some type of RFI/ EMI protection. I bought a Nordost Purple Flare figure 8 power cord for my BlueSound Node 2i. I bought a cheater that turns a three prong EIc into a figure 8. I then plugged in my Nordost Blue Heaven which is grounded. Their was a definite improvement over the sound. At a Nordost/ Ayre/ Kef show at my local audio store I asked the Nordost rep about it. He said the cables are the same except for the ground wire and the figure 8 end. I tried it several times and had the sam sound improvement each time. I think Paul at PS Audio has talked about only connecting the ground or shield cable on the starting side. The interesting thing is the ungrounded Nordost Purple Flare still uses a three prong plug on the wall side even though their is no ground wire in the sheath. So not using the ground but using it as a shield. 

In the UK, we have 230V, but for the last 50 Years it’s been mandatory to use the 3 prong plug with an internal fuse, most appliances are supplied with an IEC Plug on the equipment end & a moulded fuseable plug on the other, these leads shouldn’t be no more than a meter (3 feet) long, all tv’s & similar equipment are usually fitted with a figure 8 cable with 2 conductors & a 3 prong fuseable plug, so potentially dangerous. I have some US gear here Audio Research which is supplied with a UK 🇬🇧 Compatible Lead of really good quality, I also have a 120V Theta Dac, which is supplied with a three prong 🇺🇸 lead, but equipment is fused, I now live in France which has 3 prong 230V receptacles, but not fused, but everything has to have breakers on both + & -, no more than 3 sockets on each power line, there appear to be no cases where anyone has died in either case, but I am surprised. You see on social media sites that in Countries such as India, there appears to be plenty of cases where people have been zapped to Death.

Safety is of prime importance, but you are not getting the best from your audio if it does not have a grounding system.

One of the most cost effective sound improvements I've made to my system was using a two to three prong cheater plug on my amp and dac.  I previously lived for thirty years in a house that only had two prong reciprocals.  I'm still here.  On your skill saw a three prong plug is important on your stereo it can be detrimental to your sound with very little risk. YMMV 😗

Electronic engineer here. I was tinkering with a tube (valve) amp when 14 years old and got a bad shock. My father (electrical engineer) was an expert witness for some investigations into death by electrocution.

I recommend taking every step necessary to avoid having a mains electric shock. On this side of the Atlantic, mains is 230V. Building standards (UK) require that gas and water pipework is earth-bonded where exposed and all sockets to be protected by RCDs.

Did you guys forget that on the positive side of the circuit there’s either a fuse in the fuse box or a circuit breaker. So even if you’ve got one hand on something that’s ungrounded and you happen to touch something that shorts out… then you’re either blow the fuse in the wall or tripped the circuit breaker and/or any fuses that are inside the amplifier. There is lots of safety built into the whole system.

So even if you’ve got one hand on something that’s ungrounded and you happen to touch something that shorts out…

Say what???

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If you get between a hot 120V line and a grounded object, say from one hand to the other hand you will have a 120V potential from hand to hand. The resistance from one hand across the chest, through the heart, to the other hand can average around 1000 ohms, more or less. Really dry calloused hands the resistance might be as high as 100K ohms.

Amps = voltage / resistantance.

120V / 1000 ohms = 0.12 amps. (120mA) (Ventricular fibrillation of the heat)

If you cannot let go quickly the resistance can drop to 500 ohms or less.

120V / 500 ohms = 0.24 amps. (240mA) (Ventricular fibrillation of the heat)

In either case if the amp rating of the fuse in the equipment is greater than 0.12A or 0.24A it will never blow.

Forget about the regular 15A or 20A circuit breaker in the electrical panel tripping.

If the breaker in the electrical panel is a GFCI, and is operating properly, it will trip open between 5mA to 6mA.

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Raysmtb, fuses and circuit breakers are to hopefully keep your house from burning down in an over-current situation. You can be electrocuted many times over before a breaker trips.

Yet search as I may, I can't find one situation where someone was killed or seriously injured from an ungrounded piece of audio equipment.

None of them are around to give their testimony anymore.
(They are all wearing halos now 😇)

Did you guys forget that on the positive side of the circuit there’s either a fuse in the fuse box or a circuit breaker. So even if you’ve got one hand on something that’s ungrounded and you happen to touch something that shorts out… then you’re either blow the fuse in the wall or tripped the circuit breaker and/or any fuses that are inside the amplifier. There is lots of safety built into the whole system. I was told that’s why our appliances run on 120 V 20 A maximum. That’s because even if you end up grabbing a hot wire with your finger and you happen to have the other finger the ground wire or the neutral it’s not going to kill most people. It might screw up someone’s pacemaker and in a very rare instance might hurt someone. I’ve done it numerous times probably once every few years over the past 20 years of construction work. Either I got zapped by a tool for a bad extension cord or a wire etc. our system is pretty safe. I know there’s outlier situation but it’s pretty rare of hearing of anybody getting electrocuted from a home appliance. 

I recently bought a Zero Zone tube preamplifier.....It has a three prong plug but the ground terminal is not connected. How can they sell this in the USA (Especially Illinois) where in many states,  everything with a plug needs UL approval.Can an ungrounded piece of equipment still get UL approval?

UL isn't required in US. Its a good idea.

Forty plus years ago I don’t recall any consumer electronic equipment that used an EGC, (Equipment Grounding Conductor). Late 1970s and earlier consumer electronics came with a two wire non polarized plug. (Though the home you were living in may have had polarized 3 prong grounding type wall outlets).

Go back to the late 1950s and earlier the wall outlet found in our homes was just a 2 wire non polarized wall outlet. NO EGC back then...

Back in those days for a person to receive and electrical shock from a piece of equipment with a hot chassis when touching the HOT chassis of the equipment you had to come into contact with a grounded object with another part of your body. What were the odds? What was close enough for some other part of your body to come into contact with a grounded object? Now if you were standing on a basement concrete floor in you bare feet you would definitely know the chassis was hot!. Or if you had a radio in the kitchen next to a sink and you were washing dishes and reached over and touched a metal screw reaching for the volume control on the radio, and the chassis was hot, you would find out instantly the chassis was hot. Would it kill you, probably not, but you might receive a wake up notice...

Radios and TVs built in the 1950s didn’t need an internal fault to make the metal chassis of the equipment HOT. There was a 50/50 chance of it being hot. It was the way it was wired. One AC mains conductor was connected to the chassis...

https://robrobinette.com/Widowmakers.htm

Back then Radios and TVs metal chassis were enclosed in a non conductive enclosure, case, made of plastic or wood. Knobs were made of plastic or wood. Mounting screws were still made from steel or brass. So the screws could be hot.

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Returning back to the 1960s and especially the 1970s where separate pieces of equipment were being made. Like tuners, tape players, and such. They were connected to an amp or receiver using wire interconnects. The power cords were 2 wire with a 2 prong non polarize plug. You still had a 50/50 chance of plugging the piece(s) of equipment into the wall outlet so all the equipment AC plug polarity orientation would be the same. Good thing the equipment did not have one of the AC mains conductors connected directly to the chassis.

Sill no EGC to contend with. And the equipment was fed from the same wall outlet, same circuit. Things were still pretty electrically safe in the 1970s. Even with all the metal cases and metal face plates. A person still might want to avoid standing in you bare feet on a basement concrete floor. And of course never use an AC powered radio near a bath tub. That could prove fatal... No GFCI protection in the 1970s.

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And then some ya-hoo decided audio equipment needed to be grounded. (Though not the Japanese. The first 2 wire cord with a polarized plug on audio equipment I seen was made in Japan.)

So when audio equipment started being built having a 3 wire grounded plug is when things got interesting. And of course back then there were not IEC inlet connectors on equipment. Cords were captive, solidly, connected to the equipment.

Well for those of you that can remember the dam plug wouldn’t plug into the 2 wire wall outlet... That’s why the 3 wire to two wire adapter was in invented. Not to cheat the ground. Hey everything still worked the same. None of the audio equipment was grounded.

 

Problem?

It’s the mix of manufactured grounded equipment, where the 3 wire grounding plug is plugged into the wall outlet, and a piece of manufactured grounded equipment that has the EGC lifted from the wall outlet, that can be a problem. In the event the piece of equipment, with the lifted EGC, has a HOT to chassis fault. You no longer have an arms length safety factor.

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Think kids, not grown up kids. There is a safety issue for sure. Kids, water, animals, electricity, NONE of that works out. 

No smiles, or grins or LOL. I'm a good Dad no shortcuts.

Well maybe a few for the grown up kids. I just want to add PLEASE video your silly A$$ when your getting boiled. To even think people don't die every year by the THOUSANDS, is just nuts. They do. It's only 100-120 VAC right? Wake up. Number one killer is 110-120 vac.

Two times I've seen ditch work with electrical accidents. 120vac. I saw 100s of safety films through the years. And knew one that survived after putting a pickaxe through a PG&E conduit. He blew up and lived.

The neighbor down the street decided to dig out his basement. I see this MESS going on in his front yard (no permits). Two weeks later the city catches on and guess what? The house is gutted by a fire. The idiot had an arcing extension cord in the crawl along with a gas leak. ALL no permits..

They took him to jail. 60 days in the slammer he's out on bail cleaning the million dollar mess. Like I'd let him near the property again if I was a neighbor.. Total NUT!

I'll never forget him saying "This is the prettiest street in town". Sure isn't any more.

Regards

Maybe a better question to ask instead of what's the harm if nobody has been killed or harmed yet due to the ungrounded gear in their possession...would be why not take the high road ( ground..pun) and ground all gear? Thereby eliminating the one in a million possibility of death..particularly IF you happen to be the one! 

Somebody once stepped on one of my power cables and killed a couple of tweeters! He didn't mean to do it, I won't name him.

I've been zapped plenty of times by ungrounded equipment.

If you play with any electronics enough...You'll get "zapped"...But that's not dead or injured....

I recently bought a Zero Zone tube preamplifier.....It has a three prong plug but the ground terminal is not connected. How can they sell this in the USA (Especially Illinois) where in many states,  everything with a plug needs UL approval.Can an ungrounded piece of equipment still get UL approval?

 

I've been zapped plenty of times by ungrounded equipment. I used to do most of my hobby work in my little shop in my basement. Eventually I learned to plug the equipment into an isolation transformer since the zap factor could be unpleasant. 

More than likely, the addition of the grounding conductor was due to someone getting electrocuted or injured by an appliance in another industry, such as a clothes dryer, stove, etc.  Since the gear in our hobby is considered "appliances", it would make good business (and legal) sense to just move over to 3-conductor power cords just in case, on the 1-in-a-bazillion chance someone got injured touching the metal chassis on an amplifier and there was a fault inside, electrifying the chassis. 

That's my guess, anyway.