I am coming out of a 1600 amp 3ph 120/208 fused switch feeding a bank of 1ph meter with 4 sets of 500 mcm in 3 1/2" EMT. The AHJ wants me to use bonding bushings on the EMT run & pull a 4/0 ground in one of the coduits. Is this correct, i have never used bonding bushings on a fused run before and never had a problem.
bonding bushings
- Thread starter patl
- Start date
- Status
- Location
- Massachusetts
Re: bonding bushings
No, the NEC does not require bonding bushings on this feeder.
The NEC does not require an EGC run in EMT.
If you decide to run an EGC it would be a violation to only run it in one of the raceways.
If you choose to run an EGC with parallel conductors you must run an EGC in each.
No, the NEC does not require bonding bushings on this feeder.
The NEC does not require an EGC run in EMT.
If you decide to run an EGC it would be a violation to only run it in one of the raceways.
If you choose to run an EGC with parallel conductors you must run an EGC in each.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Re: bonding bushings
Is this feeder fused at 1600 amps? If so, he should have a problem with the 4 sets of 500MCM.
Is this feeder fused at 1600 amps? If so, he should have a problem with the 4 sets of 500MCM.
- Location
- Massachusetts
Re: bonding bushings
Did not even notice that.
- Location
- Massachusetts
Re: bonding bushings
The 4 sets of 500 kcmil are only good for 1520 amps, you can not move up to the next standard size OCP at this level. you would have to use a 1,200 OCP or run 4 sets of 600 Kcmil
I am not following you.
The 4 sets of 500 kcmil are only good for 1520 amps, you can not move up to the next standard size OCP at this level. you would have to use a 1,200 OCP or run 4 sets of 600 Kcmil
Re: bonding bushings
Vanwalker,
As iwire and infinity have stated.
500kcmils-Table 310.16 @75 degree C column(copper).
380 amperes x 4=1520 amperes
*see 240.4 Protection of Conductors
240.4(B)(3)Quote:The next higher standard rating selected does not exceed 800 amperes.
240.4(C)Devices Rated Over 800 Amperes.
Quote: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 Standard Ampere Ratings.
240.6(A)Fuses and Fixed-Trip Circuit Breakers.
(you ask for code referances)
Vanwalker,
As iwire and infinity have stated.
500kcmils-Table 310.16 @75 degree C column(copper).
380 amperes x 4=1520 amperes
*see 240.4 Protection of Conductors
240.4(B)(3)Quote:The next higher standard rating selected does not exceed 800 amperes.
240.4(C)Devices Rated Over 800 Amperes.
Quote: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 Standard Ampere Ratings.
240.6(A)Fuses and Fixed-Trip Circuit Breakers.
(you ask for code referances)
charlie
Senior Member
- Location
- Indianapolis
Re: bonding bushings
The reason four sets of 500 kcmil can't be used with a 1600 ampere overcurrent device is that the overcurrent device uses the conductor for a heat sink. The wire itself will not have a problem and the conductor damage curves show that.
The reason four sets of 500 kcmil can't be used with a 1600 ampere overcurrent device is that the overcurrent device uses the conductor for a heat sink. The wire itself will not have a problem and the conductor damage curves show that.
- Location
- Massachusetts
Re: bonding bushings
And here I thought the reason I could not do that was the NEC.
And here I thought the reason I could not do that was the NEC.
hardworkingstiff
Senior Member
- Location
- Wilmington, NC
Re: bonding bushings
You DA MAN dillon.
You DA MAN dillon.
- Status