I have a customer who has had a Hot tub wired, and told the electrician to pull big enough wire to be able to wire pool pump motors etc. in the future. I come out to the job and he has # 6 or # 4 wire pulled to a 4 circuit panel, with a 60 amp. GFI breaker feeding the hot tub. In order to find out if this feeder is big enough, I will have to know what size motor is in the hot tub, the motors for the pool, then add 25% for the largest motor, then add the load for the heaters on the hot tub, and the load that will be pulled by the pool light. They want 2 outlets also. Are these outlets to be figured at 180 volt/amperes per outlet? Thanks... Steve
Also when figuring the feeder for a dual voltage motor, don't you have to calculate according to the highest amp rating to determine the wire size for the feeder? Thought I read this somewhere in the code, but can't seem to find it. Thanks again .. Steve

You have to use the "high speed" rating of a 2 speed pump unless there is some kind of interlocking. I think some package spas interlock the heater and high speed of the pump but they are usually the 120v setup of the spa.

gfretwell, I don't think you understand exactly what I was asking. I'm not dealing with the hot tub only, but with the swimming pool pumps also. But that is a help anyway. Does anyone know the code reference for calculating the highest amp rating for the feeder size? Thanks Steve..

Most of the pools I do are for 120/240 and 14/7 amps. The pool light if low voltage is 2 1/2 on the primary side of xformer. You need one circuit for the pool pump and one circuit for the pool light. The pool heaters we use are gas. Hope this helps.

Use 125% of the spa pump on high, the heater, the pool pump at FLA and the light. I am not sure what the receptacle is worth but I would ignore it and round up from the rest.

gfretwell, When taking the pool pumps, do I take the FLA at the higher amperage at 115 volts, or do I take them at 230 volts where they will be operating at, and do you know the code reference? Thanks Steve..

Use the FLA as they are jumpered when you install them. If this is 240, use the 240 FLA

Greg, thanks for the info. I don't know where I got that you have to figure the feeder on the highest rating. One of them things that somehow got stuck in my mind I guess. One thing for sure, the feeders certainly will be big enough on some of the past jobs I've done:)

I agree with Greg on how to size the moor loads.

I will add that the GFCI main breaker would concern me if it was my job.

With all the equipment you will have connected to the GFCI it is my opinion the cumulative leakage current will cause nuisance tripping of the GFCI main.

In my opinion it would be a more reliable installation to provide GFCI protection for each branch circuit that requires it and replace the 60 amp GFCI main with a standard 60 amp breaker.

Bob

If your equipment is tight I doubt you will leak enough to trip the GFCI. Finding the bad part might be hard if you do get nuisance tripping once in a while tho.
The GFCI that feeds my outside lights around the pool and patio is one of those things. It feeds 6 motion detectors, a couple receptacles, a dimmer and over a dozen luminaires. When this one trips I have a challenge.

I am not sure you understood what I was trying to say.

I was not talking about water leakage.

Almost all utilization equipment has some current leakage, the more equipment connected to a GFCI the less 'headroom' that is left between O ma and the trip level of the GFCI.

Of course your right it may work fine, on the other hand it may cause nuisance tripping of the feeder, which if I am hired to do a job I want to try hard to prevent.

As much as I advocate the use of GFCIs I think using GFCI mains to accomplish this is a poor design.

If I have the choice I install GFCI receptacles at each point of use and would only connect one hardwired device to each GFCI unit.

I think I still stay with "tight" meaning rain tight. Certainly defective equipment can trip a GFCI but properly working "hi Potted" equipment should "leak" in the micro amps. A table spoon of water will surely tip that into dozens to hundreds of miliamps pretty quick.
I have close to a half mile of THHN/THWN in pipe around here and it is all GFCI. I know what trips it.
My biggest tip. Arrange wires in the J box so the connections are toward the top of the box and point the wirenuts up.
They all "leak", particularly if the wind is blowing in the triple digits

No you misunderstood. The GFI is not on the main feeder. It just goes to the hot tub out of the 4 circuit panel. If the main feeder is big enough, I will be coming back out of the 4 circuit panel,( the other two spare spaces) to get the pool pumps. I've got to go back to the job tommorrow to check and see what size breaker is feeding the 4 circuit panel. I'm guessing now that it is a 60 amp breaker since I think the wire is # 6 thhn. Steve..

It sure sounds like you will need a very sharp pencil to get this all in under 60a. If these are high E pool pumps you might make it. You are going to be at the mercy of the nameplate and the customer may get in trouble if they replace the pumps.

I think you would be surprised what the leakage is on some perfect appliances, any of the leakage current testers I can find on line work in milliamps.


I will see if I can find some real numbers from a standard.

Even the length of the circuit on the protected side of a GFCI can start adding some leakage due to capacitance coupling with the EGC.

Of course water can trip it.....thats the whole idea is it not?

The "half mile" is not an exaggeration. I started with 6 500' spools and I am almost out of wire. When I trip a GFCI I find a box with water in it.

Greg, I checked the hot tub today. The amp rating on the cover said 24/34. I don't know what the 34 was, because there was only one voltage rating (240 volts). I don't know why they put a 60 amp breaker ahead of this, unless they were allowing for the "start up". I took the biggest motor which was a 3/4 hp that had a nameplate of 6.4 amps at 240 volts X 125% = 8 amps
plus the other cleaner motor at FLA = 5.5amps
plus the hot tub FLA of 34 amps( ? )=34.0
Total amps 47.5 **
This still leaves some for the pool light
and recpts.
#6thhn in the 60 degree column is good for 55 amps. If the terminations on the panel are listed for at least 75 degree, and I'm sure they are, I can use the 75 degree table which allows me 65 amps. Am I correct? Thanks.. Steve

Yup that must not be a very big hot tub.
Mine is on an 80a .
11 kw heat, 2HP jet pump and 3/4 circulation pump