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Dedicated Lines - 32 amps possible?

I no electrical expert and am planning to install 2 dedicated lines (220v, 32amps) each. Is this possible or overkill since almost everyone else is using 20 amps.

Here is my scenario:

Line 1 :
- Installed JPS AC power in wall cable (80 ft) from panel and will be used for power amps only.
- incoming power is 230v 63 amps, electrician already installed a separate MCB, ELCB, and i have the choice of installing either a 20 or 32 amp Type C breaker. This is seperate from the main box, he tapped the power out to the separate box.
- this line will run to an isolator near the equipment (basically it is a big ON/OFF switch). At this Isolator, this will split going into 2 x Duplex Furutech Gold Receptacles...
- amps used are McCormack 225 monoblocks and possibly Earthquake Grand Cinenova 5 channel...This amp has a 4kva trans inside which the dealer says, tends to trip breakers due to high current draw during start up..thus the 32 amp question...
- simplistic thought...since this line will split into 2 outlets, if all three amps are on, will the current draw be high enough to warrant the 32 amps or will 20 amps be enough..

Line 2:
- this is just normal Romex wire which is 6mm dia each (I think this is either 12 or 10 guage)...
- this is also running from the separate box that is installed...I have the option of either putting a 20 amp or 32 amp Type C breaker....
- this will also go to a separate Isolator that will go into a Furutech duplex receptacle...
- this outlet will be for the Hydra 8 that will connect the CD, DVD and Pre-amp....

Both lines are running together and because of the plastic trunking, there is a plastic separator between the cables....

So, should I go to 20 amp breakers or 32 amps...

Thanks for your advice.
teck5
12 responses Add your response
elberoth2's avatar
elberoth2
1,223 posts
 
Most ppl use 20A on 115V lines, which translates to 10A on 230V line (W = V*A). 20A is enough for you.

I'm not sure if even 32A would be legal/safe on your lines.
nsgarch's avatar
nsgarch
2,524 posts
 
You can use 32 amp breakers but there are two drawbacks I can see:

1.) They may not protect your equipment (trip quickly enough) in case of an internal component failure or partial short.

2.) You will have to use very heavy (and expensive) wire in the wall to comply with code requirements for 32A circuits, and then how do you connect 8AWG conductors to standard, even 20A, receptacle hardware?

If you are that worried about your amps tripping breakers, I think it would be more cost effective in the long run to give them each their own 20A circuit. By the way, even with 20A circuits, if you're 80 feet from the panel, there is going to be voltage drop. I suggest you go up one conductor size in the wall (like 8AWG instead of 10AWG) and then reduce it back down to 10 or 12 AWG in a make-up box near the outlets so it can be connected to the receptacles. (Remember, it's only a 20A circuit, so you ARE allowed to reduce the wire size down to code size before the receptacle.)
.
jea48
4,324 posts
 
Teck5, what country do you live in?
teck5 OP
47 posts
 
Hi Everyone,
Thanks for the responses so far...Some of the codes may not apply as I am not in the US.

Jea48: i live in Singapore.

Basically the JPS cables are 10 Guage and my "Romex" type cable is also in the same range. These cables are able to take 32 amps....

So am i on the right track on should I just stick to 20 amps...

Thanks for the advice.
jea48
4,324 posts
 
Grand Cinenova 5 channel...This amp has a 4kva trans inside which the dealer says, tends to trip breakers due to high current draw during start up..thus the 32 amp


4000 va divide by 230V = 17.39 amps. That amp should have its own dedicated circuit. That is if the amp will be on at the same time as the other amps. And with that said I doubt a 20 amp breaker would withstand the initial inrush current if the primary of the transformer does not have a soft start circuit.

Code in Singapore, I have no idea. In the US the largest breaker that could be installed on a branch circuit feeding a NEMA 5-15R duplex receptacle or a 5-20R receptacle is 20 amps.

What is the current rating for your receptacle, is it rated for 32 amps?

You really need to direct your questions to the electrician that did the electrical work for you.

teck5 OP
47 posts
 
Hi Jea48,

Thanks for the quick response..

Since I am running a separate box for these 2 lines (note that the main incoming is still 63 amps), my electician says that using 32 amp breakers are okay...this is also okay with our code since all is dependent on the incoming power. Please take a look at the link below...it has photos of the install...hope i downloaded it correctly..

http://pg.photos.yahoo.com/ph/tkchia5/album?.dir=873fscd&.src=ph&store=&prodid=&.done=http%3a//photos.yahoo.com/ph//my_photos

He has installed Isolators near the receptacles, which is a big ON/OFF switch (which has and earth line), this will then run into the US style duplex outlets (115v 20amp)...see link below...a check with Furutech, say's that 230v 20 amps running through is not a problem...

As you can see from the photos....he has not terminated them to the furutechs as I am waiting for them to come...

http://www.furutech.com/produ_2.asp?ProdNo=73

As for the Earthquake amp, please take a look at the specs below...THis amp will be an add on later... have not yet decided to buy it...so if it proves to be too much that I will look for a less demanding amp...

http://www.earthquakesound.com/cng_5.htm

Hope this info helps....Thanks again...
jea48
4,324 posts
 
He has installed Isolators near the receptacles, which is a big ON/OFF switch (which has and earth line), this will then run into the US style duplex outlets (115v 20amp)...see link below...a check with Furutech, say's that 230v 20 amps running through is not a problem...


this will then run into the US style duplex outlets (115v 20amp)...see link below...a check with Furutech, say's that 230v 20 amps running through is not a problem.

If I understand you correctly, Furutech told you that you could use a US NEMA 5-20R receptacle for 230V is that correct? Maybe in Singapore but not in the US.
The NEMA 5-20R can only be used on a nominal 120V 20 amp branch circuit. Never to be used on 230V, connected to a 20 or 32 amp breaker.

Maximum power that can be connected to a NEMA 5-20R receptacle:
120V X 20 amps = 2400va (residential family dwelling unit). 1920va commercial/industrial applications.

Here is what you will have if you follow what Furutech has proposed,
230V X 20 amps = 4600va. Granted the power amp would never normally draw that much power. But what if??
another example,
230V connected to a 32 amp breaker. 230V X 32A = 7360va

I notice from the picture of the amp it has an IEC male connector for a detachable power cord. Why not just buy a cord that will fit the configuration of a 230V 32 amp, or higher, rated receptacle for Singapore?

I was not able to bring up your second link.
teck5 OP
47 posts
 
Hi Jea48,

Let me check on your suggestions with the electrician...I see what you are saying....and the last thing I want to do is to mess things up...

My approach has been:
- make sure that the incoming lines are separate from the main box...with separate breakers....this is done....
- make sure that the amp line and other components line are separate...this is done....
- make sure there is enough juice....thus the 32 amps...this is done ....but realise through your questions that the receptacles may not be rated for this (esp at 32 amps)

I will check with Furutech again....just to be doubly sure..

Could you please try clicking the 2nd link again...I tried it and I was able to go through....the second link is to the furutech page...
http://www.furutech.com/produ_2.asp?ProdNo=73

Let me get back to you on this...Thanks again....
gs5556
1,218 posts
 
Contact the amplifier manufacturers and ask them about power requirements. Or better yet, pop open the fuse holders and look at the amp rating of the fuses. Bet you they are 10 amps, give or take. If they're less than 15 amps (or even 20), then they cannot possibly trip circuit breakers as the dealer claims. Hopefully, this helps.
sol322
426 posts
 
Gs5556 has a good point here, Teck5 the comment on breaker tripping made by dealer is based on customer having dedicated lines or regular house where line is shared with other electric loads?. That's my first question.
Second the distance for the in wall wire is long so Nsgrach comment on increasing this conductor size makes sense.

Key question to ask is if the amp has a soft start feature which can ease up the load during start.
teck5 OP
47 posts
 
Hi,

This is what is stated on the Earthquake site...

Fault indicators
Each block is equipped with two (10 amperes) fuses designed to protect and monitor the voltage of operating rails (+/-). Each fuse carries its own fault LED indicator that illuminates when the fuse is burnt.

Doesn't say much and I guess I will have to check... The dealer did indicate it would be be best to run a dedicated 20 amp line with a Type C breaker (this is for industrial use and is more forgiving when there is a high current draw, it will trip so quickly)

If you look in the back of the Earthquake amp, there seems to be a breaker as well...built in above the inlet...

My McCormack monoblocks (they are arriving this week, not in yet) before mods is rated at 5A/600w at clipping (8 ohms), at idle it is 1.1A/130w....after the mods estimated at clipping is at 10A/1,000w per side...so 10A each (total 20A.) if i play that loud....

For the cables, I checked...the JPS labs and the "Romex" type cables are 10 guage which can handle the 32 amps...Sorry to ask a dumb question, but why should i be concerned about the length of cable versus the guage type...???

I will be checking on Furutech's ratings, and the Earthquake Cinenova Grande (soft start feature)...
Will get back...

Thanks for the responses so far...
sol322
426 posts
 
Teck:

Cables do have a current carrying capacity based on their gauge. For short runs a cable that works fine can not perform well in longer runs due to resistance (the longer the cable run larger resistance you get) so the recommendation on thicker gauge to avoid this losses. Typically we find that gauges used in audio installations are heavier than the normal electrical criteria suggests. I've done the same (i.e. thicker) and got good results. Steady load consumption is one scenario but current peak demands are another. Just my 2 cents.
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