I have a strict 240V wiring situation (i.e., two hots + ground, no neutral) with a hot tub as the only load on the circuit. Now, I think it’s very prudent (and generally mandated) to have a local disconnect with a GFCI breaker...which gets tricky with no neutral.
The scenario is pretty well illustrated by this image (i.e., "Configuration 2" from this previous post)
The other post concluded that using the neutral is the way to go - and I would have posed this question over there, however:
- the topic appears to be closed for comment, and
- there's a key distinction here - there is NO feasible, code-compliant way (and trust me I’d like to) to run a neutral line from the main panel to the disconnect via any available/feasible conduit paths...there's just not
So it got me to thinking, what exactly is wrong with “Confugration 2”??
And before there are a ton of knee-jerk "it's not code" or "you can't do it that way" responses (as in similar posts), please bear with and hear me out to help consider the best, safety-minded solution for this unique situation (i.e., the 'spirit' of the code vs. pedantry about the strict letter of the code)
- For starters, I realize that the EGC (i.e., green 'ground wire') is never intended as a substitute or equivalent for the neutral wire and that the two should never be tied together anywhere but the main panel - not disputing that, not proposing that
- I also get that since a GFCI breaker ‘monitors’ the current traveling through the valid conductors to infer a 'ground fault', all those conductors must be connected to/pass through the GFCI
- And lastly, while many 240V appliances do in fact also have 120V circuitry (e.g., the clock on a stove) where the neutral is a key component and a valid conductor, in my case there is NO NEUTRAL anywhere and therefore the neutral never could/would/will be one of the valid conductors
And some validation tests show that:
- No surprise, the GFCI won't work if the pigtail is not connected (to something) so my contention is that the GFCI must have the neutral (or something) as a proxy/reference to ground to properly function
- And lo and behold, the normal, expected functionality is there when the pigtail is connected (gasp!) directly to the ground as depicted in the image
So the outstanding questions are:
- Is the GFCI breaker purely passive/electromechanical and only 'activates' and trips (e.g., electromagnetically) when enough current flows throught an unintended path?
- OR is there also an active/electronic component in there that's continuously consuming (probably minuscule amounts of) power and sending (probably minuscule amounts of) current along the ground line in this setup?
- Even if the latter, it's reasonable to think that the amount of current going along the ground line must be so small as to be below the threshold of the GFCI line and therefore relatively "safe", correct? (until it isn't, like when you hit the 'TEST' button or a legit ground fault)
Sooooo...given all that, would you agree or disagree that - in a situation where there is/can be no neutral - it's at least better to have a GFCI there connected like this than to have no GFCI at all?
(and bearing in mind that I agree nobody should opt to do it this way if they can avoid it)
Thanks and curious to hear the discussion...