Hot tub Breaker tripping on 120V connection, 240V works fine
 

While trying to get a hot tub up and running, I have a breaker problem.


With any connection with 120V (using a line and neutral wire), the
breaker trips.

If I only connect 240V connections, being the pump and the heater, with
the contactor and pressure switches bypassed, the tub runs and heats
up.

On 120V, there is only a light bulb, and a contactor, which is fed
through a pressure switch and limit switch.

If either of the two, light / contactor, are connected to 120, the
breaker trips.

The possibilities I see a
1. Both the light circuit, and the contactor are shorted to ground.
2. The electrician who installed the 240V circuit did something
strange.

I am having trouble beleiving both circuits are shorted, that would be
too much of a coincident.

I do not completely understand 240V breakers. Could I have a version
that requires complete current balance on 240V? If only 240V
connections are attached, there should be no current on the neutral
wire. This case runs fine.

In the event 120V is connected, current (a small amount) should exist
on the neutral wire.

Why is the breaker tripping???

I suppose my next step could be to detach the wiring from the tub, and
just try to power a lamp or something to ensure it is nothing in the
box...

Is the breaker that's tripping a GFI breaker?

Mikepier wrote:
Is the breaker that's tripping a GFI breaker?

I believe so... I had it installed by an electrician, and it should be
to code for a hot tub.

Before I call him back, I would like to know if it is indeed somthing
he did, and not me! Otherwise, I have to pay!

Just to add, the electrician installed the 240V before I had the hot
tub. I connected the wires to the hot tub myself, but am fairly
confident I made all the right connections. The 240V works, but it
appears that any 120V connection (between either of the hot wires to
neutral) causes the trip.

Did you run a new wire for this 120 V that you wanted? or are you grounding
out one of the 240V sides?

"Did you run a new wire for this 120 V that you wanted? or are you
grounding
out one of the 240V sides?"

He doesn't have to run a new wire. A 240V spa is run with two hots, a
neutral, and a ground. The heater runs on 240V, the pump can be either
240 or 120, and the blower, lights, etc run on 120V.

I would try just hooking up a test lamp without the spa connected to
one leg of the 240V and the neutral. See if that trips the breaker,
which should be GFCI. If it doesn't, then you know the problem is
somewhere in the spa.

I guess I need to know how a GFCI breaker works with 240V...

I believe with a 120V circuit, if the amount of current on the hot wire
does not equal the current on the neutral wire, the breaker will trip.
The theory being the current is going somewhere unwanted, like through
your heart...

However, with a 240V circuit, with 2 hots and a neutral, how does this
work? It would seem my breaker is tripping if there is any current
difference between the two hots, in which case using 120V is not
allowed.

OK why don't you grab an extension cord and run that to the hot tub and wire
in the 120 V bulb etc off of that, if the breaker resets you have a bad wire
somewhere if not your problem is in the 240 V, are you sure your using
(Red/White) or (Black/White)? I'd try the extension cord first.

"Zoner" wrote in message
oups.com...
I guess I need to know how a GFCI breaker works with 240V...

I believe with a 120V circuit, if the amount of current on the hot
wire
does not equal the current on the neutral wire, the breaker will
trip.
The theory being the current is going somewhere unwanted, like
through
your heart...

However, with a 240V circuit, with 2 hots and a neutral, how does
this
work? It would seem my breaker is tripping if there is any current
difference between the two hots, in which case using 120V is not
allowed.


Visit the web site of the GFCI breaker manufacturer-they will have the
wiring diagrams for the all possible configurations......

"I believe with a 120V circuit, if the amount of current on the hot
wire
does not equal the current on the neutral wire, the breaker will trip.
The theory being the current is going somewhere unwanted, like through
your heart...

However, with a 240V circuit, with 2 hots and a neutral, how does this
work? It would seem my breaker is tripping if there is any current
difference between the two hots, in which case using 120V is not
allowed. "

I believe with a 240V GFCI, at any point in time, what goes out on one
240V leg must equal what comes back on the other plus neutral. If any
current goes somewhere else, eg through you to ground, it trips.

"Zoner" wrote in message
oups.com...
Just to add, the electrician installed the 240V before I had the hot
tub. I connected the wires to the hot tub myself, but am fairly
confident I made all the right connections. The 240V works, but it
appears that any 120V connection (between either of the hot wires to
neutral) causes the trip.


That is correct. By pulling 120 volts from one side of a 2 pole GFCI
breaker you are creating an imbalance which trips the breaker by design. If
your hot tub requires a 240 volt circuit and a 120 volt circuit you will
need to run a separate 120 volt line. You cannot tap off of one side of the
two pole GFCI breaker. Did your electrician know about the 120 volt
requirement when he installed the wiring?

How many amps is the 240 volt line rated for?


John Grabowski
http://www.mrelectrician.tv

"That is correct. By pulling 120 volts from one side of a 2 pole GFCI
breaker you are creating an imbalance which trips the breaker by
design. If
your hot tub requires a 240 volt circuit and a 120 volt circuit you
will
need to run a separate 120 volt line. You cannot tap off of one side
of the
two pole GFCI breaker. Did your electrician know about the 120 volt
requirement when he installed the wiring? "

That's strange, cause I have a 240V line with GFCI in the breaker box
that is run to my spa. It's a conventional 240V line, two hots,
neutral, ground. The spa uses 240V only for the heater, everything
else is 120V. And it works! I assumed a 240V GFCI worked by making
sure that the sum of the currents on the two hots and neutral was zero.

Looking at some website, it appears their are two different flavours of
240V GFCI breakers. 1 supports the 120/240 mix, and one is strictly
only 240. Looks like my electrician gave me the wrong one.

I'll give him a call... There seems to be two ways to fix it. 1) Get a
new breaker supporting the mix mode, or 2) Run a seperate 120V GFCI,
which my outlets on the house already are.

"Looking at some website, it appears their are two different flavours
of
240V GFCI breakers. 1 supports the 120/240 mix, and one is strictly
only 240. Looks like my electrician gave me the wrong one. "

That's exactly the conclusion I just came to also! At least it's easy
to fix. The electrician should switch it and only charge you the price
difference. Sounds like he wasn't familiar with spas, as all the ones
I've seen need both 240 and 120V.

Zoner wrote:
Looking at some website, it appears their are two different flavours of
240V GFCI breakers. 1 supports the 120/240 mix, and one is strictly
only 240. Looks like my electrician gave me the wrong one.

The GFCI has to have a neutral connection - a white wire from the GFCI
to the neutral bar and a screw connection to connect the neutral to the tub.

Bud--