100A or 125A for pool & hotub subpanel


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Old 05-24-23, 08:36 AM
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100A or 125A for pool & hotub subpanel

I have a new home, and it currently has a pool with just 15A breakers for lights and pump. We got a quote for a heat pump and the guy said we'll need a 50A breaker for the pump.

We plan to add separate hottub which I know will need a 50A breaker as well.

The current subpanel doesnt have enoguh space for the extra two 50A breakers so I will add an 8 space subpanel.

Question is, can I use a 100A subpanel or do is it better to go with 125A?

I need a ground bar kit?
 
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Old 05-24-23, 09:37 AM
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For the min cost of the larger panel it is cheap insurance that you will be covered for some future need!
 
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Old 05-24-23, 01:48 PM
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A panel can always be larger in amperage than required. Never smaller.

Yes you will need ground bars.
Most spas require 50A @ 240v. This would be two wires plus a ground.
Some spas require 50A @ 120/240v. This would be three wires plus a ground.
You are required to have a disconnect and a receptacle near the spa.

Your pool sub panel will require three wires and a ground.
Any ground wiring to a pool or spa must be insulated.
No buried UF feeders.
 
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Old 05-24-23, 02:37 PM
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Question is, can I use a 100A subpanel or do is it better to go with 125A?
That will depend on what size breaker you are going to feed it with. 100A or 125A?
 
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Old 05-24-23, 07:46 PM
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Should all the breakers in the panel be GFCI?
 
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Old 05-24-23, 07:55 PM
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That will depend on what size breaker you are going to feed it with. 100A or 125A?
I think we will just feed it with 100A breaker.

So right now, the current 4 space panel is using a 15A single pole and a 15A double. The pool only has pool lights, a filter, and a instamatic thing. We gonna add a heater with 50A and a spa likely 50A. None of the breakers are GFCI but I do see the pool lights run through a GFCI outlet box right at the current panel. See picture below. I'm not sure if this GFCI thing is only protecting the lgihts and the outlet or if it protects the whole panel.



I ordered this 8 space 100A panel.

https://www.homedepot.com/p/Square-D...RBCP/100185592

Assume his panel will work? I got the ground bar for it as well.


 

Last edited by gorth97; 05-24-23 at 09:25 PM.
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Old 05-25-23, 04:58 AM
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That panel should be fine for a 100 amp feed.

Should all the breakers in the panel be GFCI?
You can, but the NEC only requires GFCI protection for certain locations.
 
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Old 05-29-23, 04:43 PM
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For the 100 amp feed, which wire do you suggest? My dad told me 2 AWG . I checked online and I only see THHN wire for the larger wires at home depot. The description says you cant use that for residential.
 
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Old 05-30-23, 09:44 PM
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What size main service do you have. Adding this much to an existing service is a lot.

Many DIYers are not aware of the fact that adding a sub panel does not provide a higher service for the home.
Example: If you have 100amp main service coming into the home and then add a 100 amp sub panel to that service you don't now have 200amp service in the home. You will still only have 100amp service in total.

What is your home service now? What other electric big power eaters do you have now like, range, dryer, hot water heater heat etc . If you have a lot of electric appliances like these you may want to do a load calculation to see if you need to upgrade your present service to be able to handle what you plan to add.
 
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Old 05-31-23, 05:45 AM
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We ended up getting 2, 2, 2, 6 and 1.5” conduit.

Currently have a 50amp car charger, a hvac heat pump, tankless water heater, and other common appliances. Adding that 50 amp pool heat pump and adding the 50 amp hottub later this year.

Current service is 150amp from the utility provider. I actually submitted a project request a few days ago to have the service upgraded to 200 amps. I figure we wont install the hottub until the sericce upgrade and main panel is updated.

I assume if I do install the hottub early, I could alternate the pool heater and hot tub to run at different times of the day until I get the main service updated so as to not overload?
 

Last edited by gorth97; 05-31-23 at 06:12 AM.
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Old 05-31-23, 06:13 AM
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You are required to have a disconnect and a receptacle near the spa.
I assume the panel being within 5 feet of the spa will suffice? The panel itself doesn't have a main disconnect but the spa will have its breaker, which can be flipped?
 
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Old 06-02-23, 09:19 PM
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Hi guys, we are installing the 100A subpanel tomorrow. 2,2,2,6.

My dad mentioned nothing about ground rods. I just read all subpanels not in the house needs 8 ft ground rods? Is this necessary since we are running the ground wire already?

the panel is about 100 ft from the main service.
 
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Old 06-03-23, 04:42 AM
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The disconnecting means needs to be at least 5' from the tub. You will also need a GFCI-protected receptacle within 10' of the tub but no closer than 6' from the tub.

A ground rod is required if the sub-panel is feeding a separate building.
 
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Old 06-03-23, 09:57 AM
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I agree with Tolyn Ironhand: A ground rod is required at a detached structure. 8 foot rod driven all the way into the ground. The ground goes from the rob, uninterrupted to the ground bar in the panel. Be sure to use the proper ground wire connector at the ground bar. it should be rated for direct burial. The ground rob is required here even though you have a ground wire running to this sub panel because it is a detached building.

If you can not put the ground rod all of the way into the ground you may lay it at a 45 degree angle. If you can do that even because of rocks in the ground you can lay it flat under ground. You will need to find the codes online for such though as far as depth
 
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Old 06-03-23, 10:27 AM
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So if this is for a pool with no building, no ground rod is required?
 
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Old 06-03-23, 12:06 PM
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So if this is for a pool with no building, no ground rod is required?
​​​​​​​That is correct. You can still install one if you want.
 
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Old 06-04-23, 08:44 AM
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Is that an electric tankless water heater? Just asking because they usually need a lot of power.
 
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Old 06-04-23, 03:08 PM
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No, we are installing the panel for a heat pump that needs 50 amps, and a spa that will need 50 amps. Already using a 220v 15amp for the pool pump as well..

Making some progress this weekend. Got all the line and conduits laid out, now just need to make the connections.





 
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Old 06-04-23, 05:21 PM
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Just an FYI: You are not supposed to install the wire until the conduit is completely installed. PVC conduit is also required to be buried 18" down.
 
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Old 06-06-23, 04:41 AM
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I was asking if it's an electric tankless water heater on your main panel because they usually need a lot of power and you may be maxing out your service already with it, the 50amp car charger, a hvac heat pump and other items. Is your stove electric?
 
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Old 06-06-23, 04:54 AM
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Ah gotcha. The house is currently being renovated. The 200 amp service upgrade finally got a date of August 12th for a planner to come by and look.

The stove is electric from the 80s. We just removed it and put in a gas stove. The water heater is a standard 50 gallon heater but we are planning to install a Takari tankless water heater which uses gas.
 
 

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