110.3(B)

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pct_elect

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800A breaker has provision for (3) 500MCM conductors per phase and is marked #3/0AWG-500kcmil.
The manufacturer makes a UL listed lug kits for that breaker to accept (2) 600MCM conductors.
Should running two sets of 600MCM to that breaker with the lug kit installed pass or fail inspection?
 
IMO, that will be question for the manufacturer.
If the lugs are listed for that breaker or the breaker is listed to take other lugs then IMO it should be OK.
 
pct_elect said:
800A breaker has provision for (3) 500MCM conductors per phase and is marked #3/0AWG-500kcmil.
The manufacturer makes a UL listed lug kits for that breaker to accept (2) 600MCM conductors.
Should running two sets of 600MCM to that breaker with the lug kit installed pass or fail inspection?
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I think it unlikely that the lug kit itself is listed.

The MCCB might well be listed to use that lug kit.

I don't see why it would even be an issue, as long as the manufacturer's instructions state that particular lug can be used with that particular MCCB.

Might be an ampacity issue if the wires are aluminum.
 
pct_elect said:
The issue is the marking on the breaker itself.
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Most breakers I am familiar with have multiple lugs noted on the breaker.

In any case, I am not sure there is a UL requirement to identify all the possible lugs that can be used on the breaker itself. The identification maybe can be made elsewhere such as in an instruction sheet.
 
pct_elect said:
Should running two sets of 600MCM to that breaker with the lug kit installed pass or fail inspection?
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Assuming copper, and assuming a 4 wire system with a current carrying neutral, make sure you install a 90? rated conductor to have sufficient ampacity.

One parallel run of 75? rated 600MCM copper does not get you there.
 
Mfr says no new labels for breakers.
This hasn't been inspected yet but the man on the job expects it to be a problem.
I'll post the outcome.
 
pct_elect said:
Mfr says no new labels for breakers.
This hasn't been inspected yet but the man on the job expects it to be a problem.
I'll post the outcome.
Click to expand...

if the manufacturer has some documentation that shows that the other lugs are acceptable, one would think that would be adequate for any inspector.
 
according to UL's Molded-Case Circuit Breaker (MCCB) Marking Guide:

21. Separately Shipped Connectors ? If the wire connectors are not provided with the circuit
breaker when shipped from the manufacturer, the breaker is marked to indicate the proper
connectors or connector terminal kit for the breaker. The terminal kit indicates the manufacturer?s
name or trademark and proper wire size.
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The wording requires a MCCB that does not come with terminals must have the acceptable terminals marked on it. This one came with terminals so no marking is required.

Note that the wording very carefully does not say that only terminals marked on the MCCB can be used.

At least that would be my contention. :)
 
That is an interesting slant. Wire size is limited to 500kcmil only when used with that lug kit which is specified on the breaker. When the AL800P6K kit is used then the mfr marking of those lugs would be valid? I attached a pix. Of course this inspector may still say " show me in the NEC code book that it is OK to run 600MCM to a breaker marked 500MCM".
 

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Your picture clearly shows the part number of the standard lug kit, which is then followed by its wire range. If your inspector cannot accept the fact that the wire range and lug go together instead of the breaker frame and wire, then I would suspect you will have problems.

But, I just checked 2 sets of Square D lug kits and they both came with 'little stickers' to be placed over the original label.
 
pct_elect said:
That is an interesting slant. Wire size is limited to 500kcmil only when used with that lug kit which is specified on the breaker. When the AL800P6K kit is used then the mfr marking of those lugs would be valid? I attached a pix. Of course this inspector may still say " show me in the NEC code book that it is OK to run 600MCM to a breaker marked 500MCM".
Click to expand...

Doesn't that photo merely show the torque values?
 
petersonra said:
The problem is going to be that you now have (2) 500 KCM conductors at the termination point and that may not be adequate for the required ampacity.
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Conservatively using the 75? column for insulated conductor 310.15(B)(16) due to the lugs on the breaker, which I am not entirely sure is appropriate for this situation, a pair of 500MCM copper is good to 760 amps or next size up OCP (240.4) or 800 amp


I feel like 310.15(B)(21) with ambient temp correction applied would be most appropriate to size the ampacity of a pin adapter being that it is essentially a free air un-insulated conductor. I would be interested to hear the debate on this.
 
The wire size is circled in red.
Got the new lug kit today and it does in fact have a sticker to put over the lug/wire info to show new values.
Should not be a problem with that.
 
luckylerado said:
Conservatively using the 75? column for insulated conductor 310.15(B)(16) due to the lugs on the breaker, which I am not entirely sure is appropriate for this situation, a pair of 500MCM copper is good to 760 amps or next size up OCP (240.4) or 800 amp


I feel like 310.15(B)(21) with ambient temp correction applied would be most appropriate to size the ampacity of a pin adapter being that it is essentially a free air un-insulated conductor. I would be interested to hear the debate on this.
Click to expand...


The problem is, when you are in an application where you need more than 760A worth of wiring. Cases where the next size up rule doesn't apply, or where one has more than 760A of load.
 
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