Parallel Cable Equipment Grounding Conductors

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Jsim4109

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Cherry Hill, NJ,USA
The drawings on our project call for a 1600Amp Feeder with (4) sets of 3/C#500 Tray Cable per phase. They terminate on a 1600Amp Frame Circuit Breaker. The typical equipment grounding conductor that comes with this tray cable is a #2Awg Copper. According to Table 250.122, this feeder must be installed with a 4/0 Copper. The local inspector is not allowing us to use this cable because the smallest cable allowed in parallel is 1/0. I know there is an exception to 250.122 for multi-conductor cable. Let me know if anyone has any ideas other than ordering custom cable.
 
Jsim4109 said:
The 500's are not adaquate. But that is a fight for another day.

Where does it state the the 1/0 limitation doesn't apply to the EGC?
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EGC's are not on the list. Inspector needs to brush up on his code. ;)

310.4 Conductors in Parallel.
(A) General. Aluminum, copper-clad aluminum, or copper conductors of size 1/0 AWG and larger, comprising each phase, polarity, neutral, or grounded circuit conductor shall be permitted to be connected in parallel (electrically joined at both ends).
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For this application you need a custom cable with a 4/0 EGC or a 4 conductor 500 kcmil using one of the 500s as the EGC. It might be that the cost of the 4 conductor 500 would be cheaper than the custom cable.
 
On the topic of (4) Parallel 500s on a 1600 Adjustable Trip CB, as long as the LT setting is set at or below 1520 and behind a lockable cover, then the 500's should be ample. Correct?
 
Jsim4109 said:
On the topic of (4) Parallel 500s on a 1600 Adjustable Trip CB, as long as the LT setting is set at or below 1520 and behind a lockable cover, then the 500's should be ample. Correct?
Click to expand...

i thought the next size up rule did not apply to breakers overs 800 amps.

C) Overcurrent Devices Rated over 800 Amperes. Where
the overcurrent device is rated over 800 amperes, the ampacity
of the conductors it protects shall be equal to or
greater than the rating of the overcurrent device defined in
240.6.
 
240.6(C) Restrcited Access Adjustable-Trip Circuit Breakers. A circuit breaker(s) that has restricted access to the adjusting means shall be permitted to have an ampere rating(s) that is equal to the adjusted current setting (long-time pickup setting). Restricted access shall be defined as located behind one of the following:
(1) Removable and sealable covers over the adjusting means
(2) Bolted equipment enclosure doors
(3) Locked doors accessible only ot qualified personnel
 
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