electric tech question

[prieff]

Looking over many instances of 240v setups and I think I have everything narrowed down as to what I want to do. Maybe the Doc can help with this almost last question.

Most people use half of the 240v supply into the control box to power the march pumps/lights/other things. Does doing that in any way mess with the GFCI from the spa panel? For instance, would running or starting/stoping a March pump trp the GFCI? Should the 120v stuff not come from the GFCI supply? If there is a ground fault on a 120 pump, would the spa panel GFCI still save me?

The way I understand how gfi works is that it flips when there is an difference in current between ground and neutral. I am probably wrong. I just wondered if using 120v from 1 leg would cause a trip or if 1 side was ground faulted, would it still save my skin.

It is convenient to run everything from the single 240v supply coming in, but I want to be sure it safely sound and correct. It seems like everyone does it this way but want to double check with an engineer type.

Paul

[DrPaulsen]

That should work. I doubt the pumps have enough in-rush current to trip the GFCI. Also, everything downstream from the GFCI should be protected, even if you split the 120V lines. I would start with this plan and then rewire it for a dedicated 120V line if you need it.

[middleTspeer]

Looking over many instances of 240v setups and I think I have everything narrowed down as to what I want to do. Maybe the Doc can help with this almost last question.

Most people use half of the 240v supply into the control box to power the march pumps/lights/other things. Does doing that in any way mess with the GFCI from the spa panel? For instance, would running or starting/stoping a March pump trp the GFCI? Should the 120v stuff not come from the GFCI supply? If there is a ground fault on a 120 pump, would the spa panel GFCI still save me?

The way I understand how gfi works is that it flips when there is an difference in current between ground and neutral. I am probably wrong. I just wondered if using 120v from 1 leg would cause a trip or if 1 side was ground faulted, would it still save my skin.

It is convenient to run everything from the single 240v supply coming in, but I want to be sure it safely sound and correct. It seems like everyone does it this way but want to double check with an engineer type.

Paul

Splitting Your 240v for 120v will work just fine off a GFI. A GFI work buy sensing the in balance of current between line and neutral about 3-5 mA. So as long as you use on of the line and neutral for your 120v you will be fine and everything coming off the 240v GFI will be protected.

Starting and stopping you March pump should not be a problem. Any motor made in the last 20+ year will work just fine on a GFI.
Travis

[kjball]

Ditto to above, that's what I did and it works just fine.

[bf514921]

now that i think about it , it should be just fine, i run my PID off of my 240 coming into my control box.