DIY Jim

I will be installing a whirlpool bath and it requires two 20amp circuits. The instructions say that I need to run 12 gauge black, white and green wires from the panel to the tub for each circuit. Can I use one set of white and green wires for both circuits or do I need to run six wires (3 for each circuit)?

Jim

kok328

If your running romex, why split hairs, just pull two runs of 12/2.

locknut

Ignoring the instructions would prove dangerous. As kok328 said, just run two 12-2s. It's just as easy to do it right as is to "jury rig" it, and what would you save? Anyhow, the single white wire would properly have to be an 8awg. Remember that you're dealing with the high current draw of these baths.

DaveyDIY

If Mfg requires it for EACH circuit, then you need to follow Mfg requirements

speedy petey

I'd be curious to see these instructions. I bet it is just a description as to how to wire it.
I have NEVER heard of a tub requiring a completely separate 120v circuit for each function.
There is absolutely nothing wrong with running a MWBC to these two items, unless of course the instruction really do forbid it.
You could use a two-pole GFI breaker and not have to worry about a GFI under the tub.

triple D

In my neck of the woods, I put a double gang with the two gfi's in the toilet room or on a wall in the bathroom, whichever is adjacent to tub area. There are many tubs these days that require two separate circuits. These types of tubs employ a water pump and an in-line heater. Two 12-2's from panel on single pull breakers is the most efficient and cost-effective way to power this unit. Keep in mind that there are usually one or two places for a ground wire to connect to the tub, like the pump and heater. These ground lugs require a number 8 copper wire to be connected to the water line feeding the tub, in the tub enclosure. If the water lines serving the tub are plastic, there is no requirement to hook a wire to these ground lugs. Good luck...

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DaveyDIY

My Tub required a dedicated 20a run for the heater
A 2nd run was needed for the pump - but it did not indicate it had to be dedicated. I also used the 2nd run for the electric radiant floor heat
Then I have the standard 20a dedicated run for the rest of the bathroom. Lights are on another shared circuit

If you have a MWBC - is one side of this with a shared neutral considered dedicated by code?

speedy petey

So you really think that is cheaper and easier than a MWBC???


Just a quick clarification. This description is correct, but they are bond lugs, not ground lugs.
I make this clarification so that a lay person does not think that these lugs have anything to do with grounding or the circuit ground.

speedy petey

A MWBC run to two separate individual loads IS considered two dedicated circuits.