# 1600A service



## wildleg (Apr 12, 2009)

4*310=1240 (you did say AL ?)


are you going to fuse down to 1200 ?
(over 800 amps can't go next size up)


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## 10492 (Jan 4, 2010)

wildleg said:


> 4*310=1240 (you did say AL ?)
> 
> 
> are you going to fuse down to 1200 ?
> (over 800 amps can't go next size up)


Sorry, I first typed (4) sets. I meant to hit 5, and didn't have my eyeballs on. After I reread it, I saw my mistake once they was on.


So 1530 is no good for 1600 with a connected at 1078?


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## wildleg (Apr 12, 2009)

Dnkldorf said:


> Sorry, I first typed (4) sets. I meant to hit 5, and didn't have my eyeballs on. After I reread it, I saw my mistake once they was on.
> 
> 
> So 1530 is no good for 1600 with a connected at 1078?


the conductors have to be protected at their ampacity (240.4) can't use next above 800 (240.4 B)


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## raider1 (Jan 22, 2007)

wildleg said:


> the conductors have to be protected at their ampacity (240.4) can't use next above 800 (240.4 B)


That does not apply to service conductors.

230.42(A) states that the ampacity of service entrance conductors before that application of any adjustment or correction factors shall not be less than the sum of the non continuous load plus 125% of the continuous load.

5 sets of 500 Kcmil Al conductors has an ampacity of 1550 amps and the calculated load is 1078 so the 5 500's would be suitable for the service entrance conductors.

Chris


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## raider1 (Jan 22, 2007)

By the way what is the unbalanced neutral load?

The 1/0's work for 250.24(C) but only have an ampacity of 600 amps.

Chris


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## alfein (Jun 1, 2010)

You didn't say whether this is single phase or three phase and whether the 1/0 is
a neutral or a ground. With a service you don't need a ground and if you use 
copper conductors you only need 4 conduits[380 amps x 4= 1520 amps.].

Al Fein


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## 10492 (Jan 4, 2010)

raider1 said:


> By the way what is the unbalanced neutral load?
> 
> The 1/0's work for 250.24(C) but only have an ampacity of 600 amps.
> 
> Chris


Full size nuetral, 500 AL, and the 1/0 was ground.

I forgot on the service, as alfein pointed out, I don't need the ground. 

Is it me, or when times were good, prints were good. Now when times are rough, prints are rough.

I can't for the life of me, see how a PE would spec 800A worth of rooftop heat/AC units for 208 3 phase?

If the service was done in 480V, and I install a 75Kva 208/120V trans for the recpeps and lights, this could be down a boat load cheaper.

FWIW, I have never seen a fused disconnect bigger than 600A. I can't imagine the size of a 1600A.


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## 10492 (Jan 4, 2010)

alfein said:


> You didn't say whether this is single phase or three phase and whether the 1/0 is
> a neutral or a ground. With a service you don't need a ground and if you use
> copper conductors you only need 4 conduits[380 amps x 4= 1520 amps.].
> 
> Al Fein


3 phase.

I have to do the cost thingy. I think the AL route is cheaper.


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## hardworkingstiff (Jan 22, 2007)

raider1 said:


> That does not apply to service conductors.


Chris, help me out here.

When I read article 240.3 (Table 240.3 too), it seems to say services are covered by article 240, therefore 240.(B)(3) would indeed apply. Where am I wrong thinking?


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## raider1 (Jan 22, 2007)

hardworkingstiff said:


> Chris, help me out here.
> 
> When I read article 240.3 (Table 240.3 too), it seems to say services are covered by article 240, therefore 240.(B)(3) would indeed apply. Where am I wrong thinking?


Table 240.3 shows that services are covered in Article 230.

230.90 gives us the requirements for overcurrent protection of service conductors.

You are correct for a single overcurrent protective device it must have a setting not higher than the ampacity of the service conductors. 

For multiple service disconnects and overcurrent protective devices Exception #3 allows the breakers to exceed the rating of the service entrance conductors.

I was having a brain fart.

Chris


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