im wiring a gfci in the kitchen and the outlet had three white and two
blackwires. both black tested hot when paired with only one of the three
whites or with the ground. ive tried as bunch of configs-cant get it and
have outlets downstream that wont light up-any advice?
line ( GFCI ) load
<<power source to breaker down stream outlet>>
Is this what you see? There must be an instruction sheet with the
package. Did not get one?
You won't have three black and two white wires unless they are pulled in
some type of conduit. You need to determine how they were connected to the
existing outlet. It is possible that the existing outlet was split on two
circuits, or a switched circuit. If either was the case, the break off tab
between the brass screws will be removed. In any case, separate all the
wires, then with a tester, determine the black and white "feed" wires, which
attach to the "line side of the GFCI, then try attaching the other wires to
the "load" side, and see what you get
RBM, its three white and two black. both black appear to be hot when tested
with ground. only one of the three white wires will light up the black
wires though. the other two white ones dont.
thanx for any help
ok closer inspection reveals three conduit wires coming into box where im
trying to install GFCI. One has a black a white and a red- the red is
connected to a black of another conduit. the two other conduits have just
a black and a white each.
the two free blacks test hot with either the ground or the white which
comes from the conduit running the white black and red.
any ideas on gfci line and load-what whites should go where? im pretty sure
the conduit with blackwhiteand red is my line wire.
You line wire is probably 2 phase (red white is one phase, black white is
another) feeding two different circuits downstream.
If you measure between black and red you should get 240V. Use a volt meter
to measure instead of a hot/cold probe.
You need two gfcis to protect two different circuits. If you can only fit
one GFCI in the box, then you can
(1) use only one of the two phase, in other words, combine the two
downstream black/white together on the load side of the GFCI. However, this
is probably a code violation and a bad idea. Usually builders don't pull a
2-phase line unless they have to. If this is in the kitchen, you are
supposed to have 2 independent circuits of 20A, both protected by GFCI.
(2) pick one of the two circuits to protect with the GFCI and leave the
other one unprotected
(3) install a bigger junction box and put two GFCI in there to protect two
circuits. This is probably not easy unless you have an open wall
(4) put GFCI circuit breakers in the main panel to protect these two
circuits, or one GFCI breaker and one GFCI receptacle
That's right. You cannot use regular GFCI breaker at the panel side of a
However, there seems to be a special breaker called a double pole GFCB for
multiwire circuit. Judging from the lack of hits on google, it is probably a
Here's some info I found:
What it looks like you have, is an Edison circuit, which is two hot legs
that share a common neutral. The conduit with the three wires would be the
feeds. The red wire is a feed that just continues somewhere else. The
problem is that you cannot share a neutral of a multiwire or Edison circuit
off the "load" of a GFCI. You need to connect all three whites together with
a fourth pigtail connected to the "line" neutral of the GFCI. Leave the
black and red that are wirenutted together alone. Connect the two blacks
together with a third pigtail to the "line" hot of the GFCI. You are now
protecting that one location only. You need to go to the next outlet
downstream and install anther GFCI, and continue doing this until you no
longer have an Edison circuit involved
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