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Original Post: Garage Sub Panel and Pool Electric Install Questions

Njhokie Member

Hello!

First time user here. I've been searching and browsing for a while for help related to my install but wanted to be clear on code and ask specific questions related to my particular job in a new thread if you all don't mind!

I'll be running the electricity for our inground pool which will require me to upgrade the current sub panel in the garage to accommodate the added load.

My first questions are related to the sizing and type of wire for the feeder line to that sub panel.

I'll have the pool pump (240V/~10A), convenience GFCI (120V/15A max), extra 20A garage circuit, and a NEMA 14-50 plug for an EV charger (40A max) on the sub panel. The run will be long (80ft) through the basement, up into the attic, and then into the garage.

1a) A possible scenario I see happening is the car charging and pool pump running, which would be around ~41A draw. But it could be higher worst case. I was figuring on using a 60A or 70A breaker. Thoughts on that?

1b) Is there a bundled wire I could use (SER) or does it have to be THHN that would need to be run in a conduit? I would really prefer to avoid running conduit because of the run necessary.

1c) Does that sub panel need an insulated ground wire from the main panel, or is that only required for the run outside to the pool pad/pump from the sub panel?

I appreciate your help on this project.

Ibpooks Forum Topic Moderator

I'm assuming this is an attached garage based on context. I recommend #2-2-2-4 aluminum SER to feed the panel, breakered at 90A. For a pool panel feeder that runs inside a residence you can use jacketed cable with uninsulated ground. The panel can be 100A main lugs only, main breaker is optional. The panel will need an add-on ground bar kit and the bonding screw removed to keep ground and neutral separate. No ground rod is required.

The circuit from this subpanel to the pump motor needs to have #12 insulated copper ground and a GFCI breaker which means conduit of some type. You'll also need either a lock hasp installed on the pump breaker or a pull-out style disconnect or similar cut-off switch within line-of-sight of the pump.

Njhokie Thread Starter

Thanks for the quick reply!

Did you calculate the 90A based on 100% load of the equipment/circuits I listed? To me, I should be using 80% because they are intermittent. That would come to around 13,000VA. Divided by 240 is around 54A.

It is an attached garage.

I was going to use metal conduit buried at >6ft for the pool equipment.

Ibpooks Forum Topic Moderator

I calculated it based #2 SER is widely available and cheaper than other options, and would allow you room for expansion if you ever need it. For example #2 SER is around $1.50/ft for 90A and #6 NMB is around $2.50/ft for 60A. If your supplier carries it you can do 60A with the slightly cheaper aluminum SER 4-4-4-6, but if you have to special order or pay shipping it negates any savings and doesn't allow future expansion.

Njhokie Thread Starter

OK thanks for the explanation.

I believe I currently have a 6/3 NM-B run already in place when I wired the EV charger up. That would suffice for this application? I was thinking I would have to upgrade it for sure to add the pump and GFCI for the pool.

Ibpooks Forum Topic Moderator

It's borderline, but would probably be OK. Max breaker on the 6-3/g is 60A. If the 60A breaker trips on a regular basis you'll either need to upgrade the feeder or configure schedules such that the pump doesn't run at the same time as the charger.

Njhokie Thread Starter

I could manage that no problem. The pump and car have scheduling abilities.

Another question:

In running the NM 6/3, I'm clear on how to run it across roof joists and in the attic (protected on either side by a boards), but there's a point I have to run the NM down the garage wall (concrete). Can that be stapled on top of a board that runs down to the panel, or does it have to go in conduit?

If so, would I terminate the wire in a box above the wall, then switch over to THHN in conduit to the panel?

Ibpooks Forum Topic Moderator

Stapling the cable to a running board is OK. 6/3 is large enough that it doesn't require separate protection, but a board is generally more convenient than stapling to masonry.

Njhokie Thread Starter

I verified I did run 6/3 before, so I'll stick with that.

That run was made off a sub panel (100A) right next to the main panel (200A) in the basement as the main did not have open spots. Should I move the 6/3 60A breaker to the main, swapping with two other circuits? That 100A sub panel has a 20A circuit for electric heat in the basement (not used often), a garbage disposal, and some other lighting convenience circuits, not more than three.

Ibpooks Forum Topic Moderator

I wouldn't bother reconfiguring unless the 100A breaker is tripping under load. Code makes no limitation on the number of subpanels you can chain together inside the same building.

Njhokie Thread Starter

I'm now getting a little confused with the location of the pump and convenience outlets. I reads to me like code for the pump is 6-10 feet from the pool, and the convenience outlet anywhere from 6-20 feet from the pool. On most searches though I see people locating the pump much further away. Can anyone help on correct locations per code?

Thanks!

Ibpooks Forum Topic Moderator

Any type of receptacle (whether supplying the pump or not) must be 6 feet or greater from the edge of the pool. At least one GFCI-protected "convenience receptacle" must be 6' - 20' from the pool.

There is no minimum or maximum distance for the pump itself; nor any distance requirement if the pump is hardwired. If the pump is cord-and-plug, a cord can't be longer than 3', and the receptacle can't be closer than 6', but the pump itself could be closer within the range of that 3' cord.

The pump circuit has to be GFCI protected whether hardwired or cord-n-plug.

(Based on NEC 2017. There have been subtle changes to these rules in almost every code revision in recent memory.)

Njhokie Thread Starter

Ok great thanks for the clarification. That's about what I figured.

Does the convenience receptacle need an insulated ground wire as well, or could I use UF-B direct buried for that and forgo a conduit?

Ibpooks Forum Topic Moderator

Sorry for the weenie answer, but if it's "close" to the pool or in a somewhat enclosed area around the pool or pool equipment, use PVC conduit and an insulated ground. If it's closer to the 20' mark and out in the open, UF-B is OK.

The lack of clarity is because in 2017 code, areas around the pool are now considered a corrosive environment due to the chlorine fumes; however the language is not very clear regarding just how far from the pool water the corrosive environment ends. I think it is pretty clear that any enclosed or semi-enclosed area around the pool or pool equipment is considered corrosive though.

Njhokie Thread Starter

I consider UF-B to be more resistant to corrosion and environmental factors than THHN in PVC conduit, no?

It needs to terminate in conduit starting from 18" below grade as well right?

If I did go the UF-B route I've also read that if the circuit is GFCI protected it can be buried 12". Is that right?

Another question: I'm using a variable speed pump that has a control panel that can shut the pump off. Do I still need to install an inline switch on the circuit?

Pcboss Forum Topic Moderator

UF cannot be used for a pool. The ground needs to be insulated.

Njhokie Thread Starter

I'm not talking for the pool pump here. More so for the outlets around the pool, including the convenience receptacle.

Ibpooks Forum Topic Moderator

UF is not allowed in a corrosive environment. I believe the only candidates are rigid or intermediate threaded conduit, PVC conduit, or corrosion-resistant MC-cable (not all MC qualifies).

The control panel counts as a disconnect if it has a physical "OFF" position. Soft-off / digital-off doesn't count.

Njhokie Thread Starter

Switching conduit.

I ran into an old patio 10” deep in one 15’ section while trenching. It it permissible to switch to metal conduit for that small section then go back to pvc?

either that or I’m going to have to jackhammer it. Tried going around but ran into very large roots. thanks again for all your help!

Ibpooks Forum Topic Moderator

Yes you can switch to metal conduit for a shallower portion of the run. Another option is to try hydro-drilling under the old slab. Basically hook a garden hose up to a length of conduit and work it in-and-out to tunnel under the slab. You can often make it a pretty good distance with this technique, and since you already have a trench on either side access is pretty easy.

Njhokie Thread Starter

I’ll give it a go. That’s a good idea, would be great if it works.

What is an approved method for joining pvc and IMC? Compression fittings? Do they need to be watertight?

Ibpooks Forum Topic Moderator

Just use threaded fittings to make the connections, thread the IMC into a coupling, thread a male PVC fitting into the coupling, then glue in the PVC conduit. They do not need to be watertight. Note threaded fittings can be tough to pull through, so run a string or rope through as you assemble to make the pull much easier later on.