Backfeed or something????

Status
Not open for further replies.
melanconelectric

melanconelectric

Member
Location
West Monroe, LA
Recently remodeled an older home and installed 1500W HVL in the mast bath, one of those with heat-vent-light-night light. At trim out, i got a 2 gang switch box with one 12/2 HR coming in, dedicated. Got two 12/3 coming out ( 4 switch leg returns). In one 12/3 when I energize the blk with 120V, I get 41V on the red. No staples in the cable, NOTHING is terminated in the fixt housing, not even neutrals. And only that neutral for that cable is tied in with the incoming neut. When de-energized, no continuity-no resistence from blk to red. 12 years and I never seen this!
 
Wouldn't 300.5(I) prohibit using two 12/3 cables to this fixture? All the conductors should be in the same cable, conduit, smurf tube, etc. JMHO.:smile: I know this doesn't answer your question, though. sorry.
 
lpelectric said:
Wouldn't 300.5(I) prohibit using two 12/3 cables to this fixture? All the conductors should be in the same cable, conduit, smurf tube, etc. JMHO.:smile: I know this doesn't answer your question, though. sorry.
Click to expand...


is this 2005 NEC ? in my 2005 300.5 is labelled "Underground installations"
 
melanconelectric said:
NOTHING is terminated in the fixt housing, not even neutrals.
Click to expand...

So we have the red wire not connected to anything. When the black wire in the same cable is energized, the red wire is showing a voltage. Seems like a classic case of high-impedance meter-itis to me.
 
this is the point in time when, instead of assuming that there is induced voltage, you could pull out a megger and make sure that you don't have a faulty cable (and know for sure that the cable is clear)
 
pull out a megger--------give me a break---open the ceiling fixtures junction box----disconnect all the wires---read them out with a continuity checker to identify them and re-wire the fixture. what are the chances of a bad cable!!!
 
Issue #1 - I still say check it with a wiggie.

Issue #2 - I'm fairly sure this can be done without conflicting with 300.3(B). See diagram. (EGC omitted for clarity)
 
crossman said:
Issue #1 - I still say check it with a wiggie.

Issue #2 - I'm fairly sure this can be done without conflicting with 300.3(B). See diagram. (EGC omitted for clarity)
Click to expand...


I second that crossman. Use a low impedance type tester and see what the voltage really is.
 
41 volts to what? Neutral,Ground?
you may not have a very good bond connection.
Are you using the switches supplied with the light/fan/heat unit?
I've never been real impressed with the quality of them.
But, I do tend to agree that it's voltage that's not really there.
 
charlie tuna said:
pull out a megger--------give me a break---open the ceiling fixtures junction box----disconnect all the wires---read them out with a continuity checker to identify them and re-wire the fixture. what are the chances of a bad cable!!!
Click to expand...
Bad cable - right out of the box:

HPIM1945.jpg




Had several rolls, as a matter of fact. Must have been a bad production run.
 
JohnJ0906 said:
Bad cable - right out of the box:

Had several rolls, as a matter of fact. Must have been a bad production run.
Click to expand...
You could always use it for a line-to-line load that needs a redundant EGC.

Is that 14/4?
 
Status
Not open for further replies.
Top