1600 amp wire size calc

[electromantoo]

my question is about sizing conductors for a 1600 amp single phase service.

would 4 - # 500 MCM copper THWN-2 RATED FOR 90 C per phase be adequate

the run is less than 6 feet from ct cabinet to service disconnect

the allowable ampacities chart says 500 mMCM is good for 430 amps x 4 = 1720

Thanks for any comments

 

[charlie b]

Sorry, but no. You can't use the 90C column for ampacity, unless all the components in the circuit are rated for 90C. The one that generally gets you is the terminations. They are seldom rated higher than 75C. So you can only use the 75C ampacity. Reference 110.14(C).

Thus, four 500's are only good for 4 x 380, or 1520 amps.

 

[chris kennedy]

See above.

 

[augie47]

agree, but, to cover all possibilities: when you say "service disconnect" are you referring to one means (1600 amp breaker or bolt-lok switch, etc.) ?

 

[electromantoo]

charlieB

good answer.

We are looking into the lug rating (probably 75-c )
will have to increase conductor size, thankfully it is a very short run
Why dont manufactures just use 90-c rated lugs ?

Thanks again for an A++++ answer

 

[iwire]

We are looking into the lug rating (probably 75-c )

The lug itself may actually be rated 90 C, but the equipment (breakers, fused disconnects, etc) it is connected to will not be.

Why don't manufactures just use 90-c rated lugs ?

It would be difficult to make a breaker that could handle a 90 C conductor and still not trip early due to heat.

That said, I agree with the others, you will need 600 copper or a reduction of the over current protection.

 

[chris kennedy]

my question is about sizing conductors for a 1600 amp single phase service.

Is this a common service in other areas? 1600A 240/120 1? 3 wire system. That system at that amperage is very uncommon here. (as in I have never seen one).

 

[iwire]

Is this a common service in other areas? 1600A 240/120 1? 3 wire system. That system at that amperage is very uncommon here. (as in I have never seen one).

Same here.

 

[nakulak]

maybe you could post a pic of this service ?

 

[benaround]

Is this a common service in other areas? 1600A 240/120 1? 3 wire system. That system at that amperage is very uncommon here. (as in I have never seen one).

The good news is there is one less conductor per phase ( to upsize ).

 

[hurk27]

Probably why this is so uncommon is the fact a 1000 amp 3 phase service would give you about the same amount of KVA, and wire size would be much reduced., I have seen a few but only in a rural area where 3 phase wasn't available.