Connected Load

[Alwayslearningelec]

Curious here. Had nothing to do with anything I'm working on. I came across this.

Utility shall make available temporary electric service for the project. Electrical
Contractor shall provide new 6,000 amp (connected load) 120/208V, 3‐phase, 4‐wire service
for temporary light and power.

Now the calculated load would be different than the connected load they mention and wires, breakers would need to be sized according to the CALCULATED load. Is that correct?

 

[JoeStillman]

If the 6,000A "connected load" is continuous, then the service needs to be 6,000 x 1.25 = 7,500A. You can't buy 7,500A equipment. Even 6,000A is extremely rare.

What on earth could possibly need 6,000A for temporary? What size is the permanent service?

In my world, 6,000A connected load means you added up all the nameplates of the equipment and lights and came up with 6,000A. A 6,000A circuit breaker is not a 6,000A connected load. I get suspicious when the "connected load" is a nice round number like 20A, 400A etc. I'm suspicious that the person giving me the info doesn't mean the same thing as me when we talk about "connected load".

 

[retirede]

Since this begins “Utility shall make available….” It’s directed at the utility. They’ll likely come back with lots of questions to whoever wrote the spec before agreeing to do anything.

 

[infinity]

We did a large apartment/condo complex (two towers 700+units) we installed 3-4000 amp services for temporary power. Not sure who sold them on that much power but we barely used much of it even with temporary heat.

 

[powerpete69]

All I can think of is talking to the person that wrote that spec.... and then correcting them when you clarify how small the load actually is.

 

[Alwayslearningelec]

So should the connected load include the calculation for 125% adder of continuous loads too?

 

[LarryFine]

So should the connected load include the calculation for 125% adder of continuous loads too?

No. Connected load means everything, and ignores that things like heat and A/C won't run simultaneously.

 

[Alwayslearningelec]

No. Connected load means everything, and ignores that things like heat and A/C won't run simultaneously.

Thanks. So the connected load is NOT the calculated load.

you could have:

80A actual continuous loads
30A actual non continuous loads

But the calculated would be 130A?

 

[david luchini]

80A actual continuous loads
30A actual non continuous loads

But the calculated would be 130A?

If you calculate loads of 80A continuous and 30A non-continuous, then your calculated load is 110A.

 

[LarryFine]

But the calculated would be 130A?

Yes. (80 x 1.25) + 30 = 130.

 

[LarryFine]

If you calculate loads of 80A continuous and 30A non-continuous, then your calculated load is 110A.

No. (80 x 1.25) + 30 = 130.

 

[david luchini]

No. (80 x 1.25) + 30 = 130.

No. (80+30)=110. The calculated load is 110.

As in...215.2(A)(1) General. Feeder conductors shall have an ampacity not less than required to supply the load as calculated in Parts III, IV and V of Article 220.

 

[Jraef]

I'd be willing to bet someone double-tapped a zero when typing that up... More likely a 600A temporary service.