Does the NEC allow using Burndy reducers for oversized conductors at a feed Circuit Breaker?

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Does the NEC allow using Burndy reducers for oversized conductors at a feed Circuit Breaker?
We are installing a 60 AMP 3 phase 208 V panel. We sized the conductors at 2 AWG properly but because of the long run (200 feet) we have been asked to use 1 AWG to lower the Voltage Drop.
Unfortunately, the Square D QOB 360 60 A 3 phase circuit breaker feeding the new panel will only accept 8AWG to 2 AWG conductors.
Is it a violation if we use Burndy reducers or similar parts to allow the 1 AWG to be downsized to 1 AWG at the supply brView attachment MIKEHOLT.pngeaker?
 
If your conductor size increase is strictly related to voltage drop, so long as conductor size you tap back into does not reduce to less than the overcurrent protection provided whether it is a wire tap or that listed Burndy product don't see the issue.
 
Since you're already considering some type of crimp solution I would opt for a crimp reducer to a smaller conductor to land on the CB.

What size bus is in the panel on the other end? Another solution is to increase the size of the feeder circuit breaker to the point where the terminals on the CB accept the #1's. A 100 amp CB should accept the #1 AWG conductors.
 
Using pin reducers or a short length of smaller conductor with a suitable splice is perfectly acceptable.

As others have noted, when you increase the size of your circuit conductors for voltage drop, you must also increase the size of the EGC.

The minimum size for a 60A circuit in Al, assuming 60C termination is 3 awg. You are increasing to #1. You are required to increase your #8 EGC by the same proportional area, which in awg sizing is simply the same number of awg steps. So you need a #6 EGC.

Don't forget to check conduit fill.

Jon
 
Only issue I've had with the Burndy reducers on the bolt on style (set screws) was the added solid length sometimes gave a clearance or wire bending issue. The crimp style is somewhat smaller. Another option would be to use a reducer splice to get you between the existing size to your desired size.
 
darekelec said:
FYI You have to upsize egc proportionally
Click to expand...
winnie said:
Using pin reducers or a short length of smaller conductor with a suitable splice is perfectly acceptable.

As others have noted, when you increase the size of your circuit conductors for voltage drop, you must also increase the size of the EGC.

The minimum size for a 60A circuit in Al, assuming 60C termination is 3 awg. You are increasing to #1. You are required to increase your #8 EGC by the same proportional area, which in awg sizing is simply the same number of awg steps. So you need a #6 EGC.

Don't forget to check conduit fill.

Jon
Click to expand...
Isn't 2 steps up #4 for the 1 awg?

I did the math proportion for Cu at 75F.
#6=26240 Cm #10=10380 Cm .396 ratio

#4 would be a min EG for both 2 & 1 cu

Math for Al @ 60
#3=52620 Cm #8=16510 Cm ratio of .314

#2 EG = 20821 or #6
#1 EG = 26258 or #4
 
1) First decided what the 'baseline' conductors are. I am assuming 60C terminations, and Aluminum conductors, so a 60A circuit requires #3 conductors. Per table 8, #3 has an area of 52620 circular mils (agree with your value there)
2) Next find the area of the upsized conductors. #1 has an area of 83690 circular mils.
3) Take the ratio 83690/52620 = 1.59...
4) Find the area of the required EGC. For a 60A circuit in Aluminum, that is #8 with an area of 16510 circular mils.
5) multiply: 16510 * 1.59... = 26258... This value is approximately equal to, but slightly larger than the tabulated value for #6 conductors, 26240 circular mils per table 8.

Per table 8, the proportional area change going from 3 awg to 1 awg is approximately the same proportional area change as going from 8 awg to 6 awg. Going from a baseline of #3 to an actually used #1, I would increase the EGC from #8 to #6.

It is important to note that the values in table 8 are themselves rounded from the exact formula for awg area. Based on the exact formula, the proportional area change going from 3 awg to 1 awg is exactly the same as from 8 awg to 6 awg. We could argue if we should use the exact awg formula or the table 8 values, and if the 0.07% undersizing (based on the table 8 values) is permissible.

We can also discuss if the 'baseline' for this circuit is #3 or #4 (which would be allowed if all terminals were 75C rated). If the baseline is #4, then the area change is 3 awg units, which would require a #5 EGC. Since you can't generally buy #5 Al conductors, you would end up using #4.

Side note: the defining equation for awg is a continuous exponential function. If you ask me the cross section of a 7.6 awg conductor, I could calculate it. As a _practical_ matter, wire is sold in certain sizes, and an electrician would not install #7 THHN or #5 XHHW. If you had some really odd application, and a big enough order, you could get it (maybe...perhaps the defining documents for THHN limit the allowed wire sizes). Usually wires are sold in even jumps of awg (8,10,12,14...) but I've seen #3 and #1 awg. For magnet wire used in motors, it is easy to order by the half gauge, and I've used things like 16.5 awg wire when I was trying to optimize the slot fill.

-Jon
 
Most pin adapters have a solid pin, and the terminations on the OCPDs are only listed as suitable for use with Class B or C stranded conductors. There are a couple of pin adapters that do have stranded pins.
Also there is one breaker manufacturer that says you cannot use these because of the wire bending space issue. In their opinion, the wire bending space starts at the point where the field conductor is connected to the adapter, and there is not enough space between the adapter and the side wall of the panel enclosure.
 
A box or enclosure adjacent, to splice down to the right size is truly the best way to do this. I am pushing my contractor right now to get the next frame size breaker (I-line) frame, and just turn down the trip setting. You get the larger lugs, no splices or crimps or pins. For solar application, we absolutely don’t use pins
 
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