Preface: NO I’m not an electrician and yes I can and may have to call one for the following, however I thought I’d throw this out to all the experienced BT sparkys first.
I have an intermittent problem with an 15amp exterior lighting circuit – 6 garden lights (old style, “mushroom”) and 1 outlet, run underground in PVC conduit, on a GFI breaker. The breaker will trip periodically, usually after rain. This occurs once every 2-3 months. Reset the breaker, all fine for another couple of months!
I have opened and inspected all the j/boxes & fixtures, to look for a possible short or moisture….all appear OK and dry (all the obvious ones, there are probably buried boxes somewhere). The breaker has been replaced.
Is there any way to trace this type of problem short of getting out the shovel?
Also, does this circuit have to be on GFI brkr?…most I’ve seen are on std, 15amp with GFI outlet.
Any advice would be appreciated.
Thanks
TN
Replies
In exepnsive tone tracers will not work with the wires under ground.
There are expensive ones that Locator services and some electricans have that can trace it.
If the wire is in PVC conduit for the full run it can be buried at 18". But Conduit might have been used only to protect UF cable above the ground. If that wiring method was used then either the wire has to be 24" below ground or it has 12" deep and protected by GFCI.
If the cable is 24" deep or in conduit the full run and 18" then you can replce the GFCI breaker with a standard breaker and at each receptacle.
"If the wire is in PVC conduit for the full run it can be buried at 18". But Conduit might have been used only to protect UF cable above the ground. If that wiring method was used then either the wire has to be 24" below ground or it has 12" deep and protected by GFCI."
"If the cable is 24" deep or in conduit the full run and 18" then you can replce the GFCI breaker with a standard breaker and at each receptacle."
Great point! This could be the case here. I believe it is some combination of the above. More info: these lights illuminate a front walkway of an apartment building on top of a parkade slab. The feed from panel in the parkade enters 1/2" EMT - thru the slab- then converting to 1/2" PVC somewhere UG. The garden area has approx 3 ft of soil over the slab.
I know there was a reason for this big $$, GFI breaker...sparkys aren't going to use them unless req'd. What is the downside to swapping it out with a reg. 15amp now? (obviously, I don't really want to "cook" anyone)
Thanks
TN
If the ENT and lights are properly grounded there won't be any risk by going to individual GFCI's.In general only the receptacles and not lights or other equipment are required to be GFCI protected. The common exceptions are things like SPA's/pools and boat lifts.Protecting the whole circuit does give a little more safety in that it will protected against some mutliple failures.And electrican can use an "megger" to check the wiring for insulation problems.Also if there is a number of daisy chained receptacles then you start experimenting with individual GFCI receptacles and with having some supply downstream devices. That will help ID the problem section.BTW, if you have plug in lights (or transformers, replace the covers with In Use covers. They are now required by the code and will keep water out of the receptacle when you have somethig plugged in.
Thanks Bill.....I only have one outlet on that circuit which could easily be changed to a GFI...will probably try this with a 15amp brkr.
TN
Just a comment: If I had a known-good CGFI breaker (you mentioned that you had replaced it) that was tripping, I wouldn't be in any hurry to replace the CGFI breaker with a normal breaker. I think the breaker is trying to tell you something...
Make sure nothing is plugged into the outlet when its raining - most of the problems I've heard about in your situation involved an extension cord left plugged into the outlet. These breakers are very sensitive to the stray voltages that can be induced by antenna-like wires and strong RF fields.
Also, make sure the wiring everywhere is clean and bug-debris free. Dirt across terminals, wetted by very high humidity, will trip a CGFI. I'd turn the breaker off and clean out all boxes, including the wires, with a wetted cloth. Clean the lamp sockets and the wiring at the socket base. Did I mention turning off the breaker before you do this?
Brooks
"Make sure nothing is plugged into the outlet when its raining - most of the problems I've heard about in your situation involved an extension cord left plugged into the outlet. These breakers are very sensitive to the stray voltages that can be induced by antenna-like wires and strong RF fields."
As you mentioned, the sensitivity to stray voltage etc. is what I thought may be the problem. I have run into this with Xmas lights messing with GFI circuits.
As far as cleaning/checking, when I did the initial inspection I did as you said. Checked all splices (re-did several that were questionable), gutted the fixtures, new bulbs, checked sockets etc. re sealed the j/boxes etc.....OK for 4 months(with rain), then it tripped again.
"I wouldn't be in any hurry to replace the CGFI breaker with a normal breaker. I think the breaker is trying to tell you something..."
yes, definitely, there is a fault somewhere....
Thanks
TN