above ground pool heater

[NYHigh]

Right now, the pool has a pool pump that is already wired up. Im adding a pool heater which is 38a.

1) Does the 80% rule apply here or should i just use a 40a circuit?

2) Should the circuit be ran in pvc from the panel or can UF be used?

3) The circuit for the pool pump that is there is not ran in pvc, it's just a gfci receptacle and the pump is plugged into it. Is this safe or should it also be ran with pvc from panel?

Im a little confused about this here guys. Any help would be great, thank you.

 

[Fordean]

rule

rule

80% applies and a good rule of thumb.

 

[NYHigh]

80% applies and a good rule of thumb.

Thank you. Good rule of thumb for what exactly everything in general or just motors and heaters?

 

[Doug S.]

I'd start w/ Art. 210.19(A)(1) ... ... the minimum branch-circuit conductor size, BEFORE ANY ADJUSTMENT OR CORRECTION FACTORS, shall have an allowable ampacity of not less than the noncontinuous load plus 125 percent of the continuous load.

It's safe to say both the pump and the heater qualify as a continuous load.


My 2?
Doug S.

 

[LarryFine]

It's safe to say both the pump and the heater qualify as a continuous load.

Especially at start-up in the spring if it's not a year-round pool. It could run for days.

I'd recommend a 50a circuit, especially if it's not a very short run. You want to heat the water, not the cable.

 

[NYHigh]

I'd start w/ Art. 210.19(A)(1) ... ... the minimum branch-circuit conductor size, BEFORE ANY ADJUSTMENT OR CORRECTION FACTORS, shall have an allowable ampacity of not less than the noncontinuous load plus 125 percent of the continuous load.

It's safe to say both the pump and the heater qualify as a continuous load.


My 2?
Doug S.

Can someone break this down in mathematical form. I kind of confused again now because im not sure where the 80% rule comes into play. Just to be clear, the pump is already wired, im just hooking up a heater which is 38a.

Ok so 38a X 1.25=47.5a. Now, if chosen to use a 50a circuit: 50a X .8=40a. wouldnt i have exceeded the 80% rule now and have to go with a 60a circuit instead???

 

[LarryFine]

Ok so 38a X 1.25=47.5a. Now, if chosen to use a 50a circuit: 50a X .8=40a. wouldnt i have exceeded the 80% rule now and have to go with a 60a circuit instead???

No, you've merely "checked your math" by confirming that a 50a circuit is adequate for a 38a continuous load.

80% is the reciprocal if 125%. You don't have to do the same thing twice, which is what your last sentence did.

 

[Doug S.]

It could run for days.

Mine ran for about two weeks on start-up this year... oops.
Memories of my last power bill will trim that significantly next spring!

Otherwise my 3/4hp pump runs about 10hrs/day, during the peak heat of the summer a little less in spring and fall. It's on a 25k gallon pool, 2am - 6am for the bugs, 12pm - 6pm to keep it chlorinated. Pools ain't cheap... next time around I'll go with a pond.:roll:

 

[LarryFine]

Mine ran for about two weeks on start-up this year... oops.
Memories of my last power bill will trim that significantly next spring!

A friend of mine made a cheap heater with a coil of black plastic tubing clamped against a black-painted plywood backing, and covered with clear Plexiglass.

In other words, he made a 4" deep 6' x 6' box with a clear lid, painted flat black on the inside, and the tubing clamped to the bottom with 1/2" one-holes.

Instead of one long coil, he made four parallel loops using T's and L's, so the heat gain was spread out among the four loops and gave him less flow resistance.

I think he used 1" or 1-1/4" for the main feeds in and out and for the T's, and reduced down to 1/2" for the individual loops. I can ask him if you want.



Pool: A hole in the back yard you throw money into. (Variation on a boat.)

 

[hurk27]

Right now, the pool has a pool pump that is already wired up. Im adding a pool heater which is 38a.

1) Does the 80% rule apply here or should i just use a 40a circuit?

2) Should the circuit be ran in pvc from the panel or can UF be used?

3) The circuit for the pool pump that is there is not ran in pvc, it's just a gfci receptacle and the pump is plugged into it. Is this safe or should it also be ran with pvc from panel?

Im a little confused about this here guys. Any help would be great, thank you.

On questions (2) and (3) see 680.21(A)(1) and (4)

Also see 680.22(A)(1)(2) as far as the existing pump pluged into a GFCI receptacle

 

[NYHigh]

Thanks guys. This should be ran in pvc with insulated ground right?

 

[Dennis Alwon]

Thanks guys. This should be ran in pvc with insulated ground right?

I don't see that anywhere in 680

Also the pool heater-- look at 680.9

680.9 Electric Pool Water Heaters.
All electric pool water heaters shall have the heating elements subdivided into loads not exceeding 48 amperes and protected at not over 60 amperes. The ampacity of the branch-circuit conductors and the rating or setting of overcurrent protective devices shall not be less than 125 percent of the total nameplate-rated load.

 

[vinster888]

heating an above ground pool. hmmmmm, mine fluctuates as much as 15 - 20 deg Fahrenheit in 24 hours. im in florida and wouldnt try. i sympathize for those who would.

 

[sparky59]

The information you need will be on the nameplate of the heat pump. If the mca is 38 amps the maximum overcurrent protection will be 50 amps. I always use thwn wire in 3/4" pvc.

 

[hurk27]

It is kind of strange that 680 only mentions wiring methods for motors, underwater luminaires, and feeders:-? I have never realized it doesn't say the same for other equipment:-?

or am I missing something?

 

[suemarkp]

What kind of pool heater is this -- resistance or heat pump? A resistance heater most likely needs the 125% factor. A heat pump will already have a 125% factor built in to its MCA value. So if heat pump, wire for MCA, and breaker per Max Breaker on the nameplate.

The pump most likely needs a 125% factor because its a motor (largest motor on a circuit gets a 125% factor added). I don't think you add another 125% factor for a motor being continuous, but perhaps. Never got a good answer to that question.

 

[NYHigh]

On questions (2) and (3) see 680.21(A)(1) and (4)

Also see 680.22(A)(1)(2) as far as the existing pump pluged into a GFCI receptacle

Doesn't this apply to just permanently installed swimming pools?

A heat pump will already have a 125% factor built in to its MCA value.QUOTE]

How do you know when the 125% factor is already taken into consideration with anything?

 

[suemarkp]

Read the applicable chapters. HVAC compressors have a 125% factor added in to their nameplate if the term used is "MCA". This is because there's a bunch of stuff to figure out that is rather complicated (fan motor, compressor, controls), so the manufacturer does it for you.

Motors usually have "RLA", and code requires that the largest motor on a circuit, feeder, or service have a 125% factor applied, This won't be on the nameplate because the motor manufacturer doesn't know if this is the largest one. On a dedicated circuit, obviously, it is the largest one there. A feeder or service requires some investigation.

For continuous loads, the code gives you a few places where it tells you something must be continuous. Electric resistance space heating is one area, and they tend to use the MCA term again on the nameplate to indicate the 125% value. If there is just a KW value or FLA number, you'll most likely have to multiply by 125%.

This whole thing is rather a mess in the code because you are to calculate things by nameplate value, but there are different types of nameplates -- some with the 125% factor included and others not on the same type of equipment.

 

[NYHigh]

Read the applicable chapters. HVAC compressors have a 125% factor added in to their nameplate if the term used is "MCA". This is because there's a bunch of stuff to figure out that is rather complicated (fan motor, compressor, controls), so the manufacturer does it for you.

Motors usually have "RLA", and code requires that the largest motor on a circuit, feeder, or service have a 125% factor applied, This won't be on the nameplate because the motor manufacturer doesn't know if this is the largest one. On a dedicated circuit, obviously, it is the largest one there. A feeder or service requires some investigation.

For continuous loads, the code gives you a few places where it tells you something must be continuous. Electric resistance space heating is one area, and they tend to use the MCA term again on the nameplate to indicate the 125% value. If there is just a KW value or FLA number, you'll most likely have to multiply by 125%.

This whole thing is rather a mess in the code because you are to calculate things by nameplate value, but there are different types of nameplates -- some with the 125% factor included and others not on the same type of equipment.

Thank you. It does get kind of crazy.

 

[NYHigh]

On questions (2) and (3) see 680.21(A)(1) and (4)

Also see 680.22(A)(1)(2) as far as the existing pump pluged into a GFCI receptacle

I just wanted to post this again so it doesn't get overlooked. My question to this answer was, "when it comes to above ground pools, do the motor and/or heater equipment circuits need to be ran in pvc? I checked these articles listed above and it seems to pertain to permanently installed pools. So i'm assuming this doesn't apply to this installation. Am i correct on this?