New Outdoor Sup-panel

I have a 240v/50amp service to my spa but the spa is only 120v so there is an extra #8 wire that is capped. I wnat to use this and the common and ground to provide power to a new sub panel for outdoor lighting, fountains, etc.

I can connect to this extra wire in a junction box and extend the common and ground from the spa's buss bars. My sub panel has space for 2 breakers ( I'm using a 20 amp and a dbl 15 amp breaker ). Should I run separate wires (what size to the hot busses from the existing or should I run 1 #8 wire and split/jump within the sub panel box? If I runs separate wires about 20 feet, what sizes would be appropriate for the 2 breakers?

What is the best way to ground this new sub panel? Ground Wire to a clamp on a pipe or rebar driven into the ground or set in concrete?

Thanks, Joe

 

I sure hope that that 120-volt spa is not protected by a 50-amp breaker. That's not safe because the spa is almost certainly not a 50-amp 120-volt spa.

You can put a subpanel on the spa wiring (often the spa already has a subpanel), and then put a breaker in your new subpanel for your spa (of whatever size is right for the spa). This would accomplish your goal and remedy the above hazard at the same time.

If the subpanel is in the same structure as the main panel, then the grounding wire between the panels is the only grounding you need or are allowed. Do not the subpanel connected to a water pipe or grounding rod. Just make sure you isolate the neutrals and grounds in the subpanel by buying a separate grounding bar kit for your subpanel (if not already equiped) and removing the bonding screw or strap (if installed).

If and only if the subpanel is in a separate structure, you'll need a grounding rod.

 

The spa is in fact 120 volt 50 amp service. It was installed by a licensed electrical contractor who does all of the spa installations for champagne spas in north Sna Diego County.

They install a 240 volt 50 amp service but the spa only uses 120 volts so there is an extra line. I think it's probably a #6 wire. The service is taken to a disconnect box and then continued to the spa enclosure and 120 volts is connected to the spa control box (heater and a 1-1/2 hp pump and a 2 hp pump).

 

It sounds like the sub-contractor installs a 50amp/240v panel reguardless of the size of the spa.But the spa in this case only uses 120v,so the contractor only used 1 leg of the feed.The FLA {full load amps} for a 1.5 Hp pump is 19.6 {at 1725 RPM},a 2 Hp is 19 to 23 amps {at 3450 RPM}.Depending upon the wattage of the heater the feed for the spa may be right, as long as both pumps dont run simultaneously.

 

Heater only runs when pumps are off. There is a low power mode for the smaller pump when the heater is on, but the heater can not operate when the pumps are on full power.

 

Joe,

The existing branch circuit may not meet the code requirements for a feeder to a panelboard that will supply a pool or spa. Answer the following with as much detail as you can.

What wiring method did the electrical contractor install? (NM, conduit with individual conductors, etc,)

If conduit, what kind?

What AWG size and colors are all of the available conductors?

Is the Equipment Grounding Conductor a green, insulated conductor or is it bare?

 

The Conduit is Gray waterproof exterior grade. I don't know off hand what it's called, but it is the typical heavy gauge stuff that you can buy at a home center. It terminates just outside the spa and becomes the gray flex conduit to the spa enclosure.

The Black and Red wires are multi-stranded copper (about 1/4" thick). I'm not sure what number but I'll check this weekend. The Ground is insulated green and appears to be #10.

I will check all of this this weekend, but it is I'm sure according to code.

 

Joe,

I didn't mean to imply that what the contractor installed doesn't meet code, only that your intended change to what is existing might not meet code. There are many more restrictions for feeders to panelboards that will contain branch circuits that supply pools/spas than there are for branch circuits that supply pools/spas.

From your description, changing the existing branch circuit to a feeder sounds doable.

 

Here's the scoop!

Red and Black wires (hot) and White (common) are #6 awg. The Ground wire is Green insulated #10.

The Conduit is schedule 40 gray NM Rigid except for the last couple of feet to the spa enclosure.

The Black, White and green wires are connected to the spa buss bars. I plan on running 1 #8 wire & 1 #10 wire from the Red wire (new buss bar in a NM J-Box inside the spa enclosure) plus extend the White and Ground to the new Sub Panel using the current sizes. The #8 wire will feed to a dbl 20 amp breaker and the #10 will feed a dbl 15 amp breaker.

The 4 circuits will be wired with #12-2 with ground, all in NM conduit with waterproof NM weatherproof boxes.

If something here isn't correct, please let me know.