pool sub panel 219 feet, 100 amp

James L said:
I wired a brand new house a couple of years ago with the most basic pool. It was just a pump, filter and one light

And they didn't need anything more than a 20 amp mwbc

Pool installer wanted a 100 amp panel. Homeowner said put whatever the pool guy wanted
Click to expand...
So more to the OP's question did you bother to size the feeder with a 3% VD based on 100 amps?
 
I'm guessing the pool contractor wants 100 amps because he's planning on using a Jandy or Pentair sub/automated system. Both can handle 100
There may be multiple pumps and other accessories needed for the project.

But like others have said, if he wants it, give it.
 
infinity said:
So more to the OP's question did you bother to size the feeder with a 3% VD based on 100 amps?
Click to expand...
To answer your question as is asked? Nope

I don't know the last time I've done a voltage drop calculation and used 3% - maybe never, especially after realizing that the target should never be a percentage. The target should be the voltage after drop

If 3% is idealized from a standard voltage of 120, 240, etc then it's pretty easy to determine what your target voltage is after subtracting 3% of that.

So what happens when your starting voltage is higher? It means your voltage drop percentage can be much higher and still hit that target voltage.

Like I demonstrated in the screenshots from the voltage drop calculator, subtracting 3% from 240 gives the same result as subtracting 5% from 245
 
Little Bill said:
Voltage drop percentage is not required by the NEC. It's only a fine print note and they are not code, nor enforceable.
Click to expand...
I agree the FPN's are not enforceable, but here in NYC they have amended the code and voltage drop is in the adopted NEC.
I have learned the hard way, the starting voltage is the voltage used for load calculations in 220.5(A), the voltage drop is based on the calculated load.
It is also now apparently in another code that covers all of NY state, so the city inspectors have been enforcing it.
I would say check your all your local codes not just the NEC.
 
Hope I am not "piggy-backing" onto this Topic. Am looking at a similar situation with adding a 100A panel with a 350' run. Am going to use 80A for the voltage drop calculation because that is all the load should ever be. It should "never" be 100A except in an overload or fault condition.
 
James L said:
.

So what happens when your starting voltage is higher? It means your voltage drop percentage can be much higher and still hit that target voltage.

Like I demonstrated in the screenshots from the voltage drop calculator, subtracting 3% from 240 gives the same result as subtracting 5% from 245
Click to expand...
I get what you are saying but generally I don't see how you can assume such a stable voltage. So you measure it and get 245, doesn't mean it's going to stay there.
Maybe they keep it real tight where you are, but here with our long 4.8KV lines it moves a lot.
 
As far as using actual voltages (which as stated fluctuate constantly) for an NEC recommendation, it would seem we would have to use other NEC requirements and 220.5(A) would be applicable.
 
Not a pool but an ATM kiosk, plan speced 100 amp panel but not feeder size

I asked for load, I think was around 20 amps

I was approved to feed 100 amp panel with #6, I think used 50 amp breaker at source panel

Value engineering! Saved customer thousands of $ and had easier day

(I charged for time talking to kiosk vendor etc plus $100)
 
You must log in or register to reply here.
Top