jamesgangnc wrote:
On Jan 21, 9:22 am, "John Grabowski" wrote:
A friend is having trouble with a GFCI breaker tripping when he turns
on the swtich for his whirlpool tub. It's not a "new" problem as it's
been happening since he moved in 5 years ago.
(This is the GFCI breaker that I asked about yesterday when I wanted
to know if you could tell what caused it to trip - a fault or
overcurrent)
The main symptom is that when he first turns on the wall switch and
the breaker trips. He goes to the basement, resets the breaker, flips
the wall switch again and the tub powers up and runs fine. This is a
consistent symptom. He hasn't run any tests to see how long between
uses he has to let everything "rest" before the initial trip will
occur, so that is an unknown.
Here are some more details and a few questions.
The circuit in question is a dedicated 115V circuit on a 20A breaker
with what my friend believes is 10 gauge wire. I haven't looked at it,
but he said that he has both 12 and 14 gauge wire at home and the wire
to the tub is larger than both of them.
On the tub motor there is one label that gives the voltage and
amperage specs:
230V / 115V 8A / 16A
There is a another label that says:
"This device must be used with a switch sufficient for a 1 1/2 HP
motor. A 30 Amp electrical supply is required."
The wall switch is rated for 30A, but as noted earlier, the breaker is
a 20A GFCI.
So here are my questions:
Is the 20A breaker the (obvious) problem?
If so, why does it trip once and then work?
If the motor is rated at 16A @ 115V, why is a 30A circuit required? If
it's for startup surges, then isn't a 30A breaker too big for steady-
state operation? It seems to me that a lot can go wrong between the
16A the motor draws under steady-state operation and the 30A required
to trip the breaker.
Thanks!
I agree with John and gfretwell.
I expect the 30A requirement is to start the motor. A motor can
momentarily draw 6x the rated current when it starts. A 20A breaker can
carry a momentary overload - this overload appears to trip it. Heaters,
if any, add to the problem.
Motor circuits have different rules than ordinary branch circuits.
Overload protection for the motor is commonly a "thermal protector" in
the motor. (Also commonly a "motor starter" with overload protection.)
The overload protection for the branch circuit is at the load end of the
circuit. The breaker is for short circuit protection of the circuit. The
rating of the breaker has to be large enough to start the motor. The
breaker may, on some cases, be significantly larger than the rating of
the wires.
Garden variety AC wall switches (not AC-DC) can be used for motor loads
up to 80% of their amp rating (up to 2HP). The 30A switch complies and
is not likely the problem.
If the manufacturer says a 30A circuit is required (which the
manufacturer did) the NEC makes that an installation requirement. The
20A breaker is a code violation. (It is likely a lot cheaper than a 30A
GFCI.)
The fix is likely to change the 20A breaker to a 30A GFCI that should
have been installed in the first place.
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bud--- Hide quoted text -
- Show quoted text -
Thanks to all.

As long as we're chatting about code violations, my friend (co-worker)
was trying to explain the mix of Black, Red, White and ground wires
that he found in the switch box.

As we were talking on the phone and he was explaining what color was
connected to what, it didn't make any sense to me. I'm fairly familiar
with simple residential wiring but motors, 220, etc. are just a tad
outside of my experience. Even given that, the wireing configuration
that he was describing just didn't make sense. He said he would take
some pictures and bring them work.

So I'm looking at the pictures of the switch box the next day and
here's what I see:

The white wire from the source is nutted to the white wire to the
tub.
The black wire from the source is attached to the switch as is the
black wire to the tub.

I'm fine with all that.

However, the Red wire from the source is nutted to the Red wire to the
tub. That seemed wierd.

At first I thought that something at the tub was always "hot" and that
maybe the switch just controlled the motor.

Then he showed me a picture of the breaker box and there it was, clear
as day:

There was a lone Red wire attached to the grounding bar. He showed me
a picture of the motor connections and there it was again: The Red
wire was attached to the Green wire on the motor.

Whoever pulled the wires used the Red as the ground wire.

*I have seen the red wire used a number of times as a ground not only in
residential, but in commercial installations as well. A simple fix is to
apply some green tape, however I am now questioning the entire installation
because of these two serious violations (Breaker size and red ground).

How about posting those pictures?- Hide quoted text -

- Show quoted text -

I didn't think the code had hard rules about wire color. Some green
tape on the ends would help the next guy to work on it.

Green tape certainly would help.

No mention of ground wires. From Derby it sounds like Romex was used -
any Romex available for a long time has had a ground wire.

As for the NEC, _in general_:
- ground wires #6 and smaller have be green or bare. They can be
tape-marked at the ends if larger than #6.
- neutral wires #6 and smaller have to be white. Again, they can be tape
marked at the ends if over #6.

It is not that hard to have (or get) green or white wire in sizes
through #6.

The other magic color is orange. If there is a high-leg delta 3-phase
system, orange is used for the high leg. Else it can be used for anything.

--
bud--