Mixing GFCI circuits with non-gfci

[goldstar]

I believe this has been discussed here in the Forum before but I don't remember what the answer was and I couldn't find it in the archives. I have a situation at a day camp where there is a DJ station inside an outdoor pavilion. I had recently converted (2) quad non GFCI receptacles on separate circuits to surge protector type and installed CH tan handle, 20 amp GFCI breakers. They are now experiencing intermittent tripping at the DJ station. I have not been back to investigate yet but I'm wondering if it may have something to do with the fact that both 20 amp GFCI circuits are in the same conduit as non GFCI circuits. Any opinions ? Thanks.

 

[kwired]

I believe this has been discussed here in the Forum before but I don't remember what the answer was and I couldn't find it in the archives. I have a situation at a day camp where there is a DJ station inside an outdoor pavilion. I had recently converted (2) quad non GFCI receptacles on separate circuits to surge protector type and installed CH tan handle, 20 amp GFCI breakers. They are now experiencing intermittent tripping at the DJ station. I have not been back to investigate yet but I'm wondering if it may have something to do with the fact that both 20 amp GFCI circuits are in the same conduit as non GFCI circuits. Any opinions ? Thanks.

If there is any interconnections between the two circuits you will trip GFCI's. About only other issue could be capacitive leakage - more likely to happen on long circuit runs, otherwise the equipment plugged in is what is likely experiencing fault conditions even if just an intermittent condition.

 

[goldstar]

That was my first thought. The run is about 100' in 3/4 EMT with other circuits and then branches off to 1/2" emt with just the GFCI circuits. This had been running for years on non-GFCI with all the DJ equipment plugged into one quad receptacle and one circuit. So, I'm guessing it's not an over-load issue but a GFCI problem. There are no interconnections between circuits. Each GFCI circuit is dedicated to its respective quad receptacle and in this case individual surge protector duplex receptacles. Thanks for the feedback.

 

[kwired]

If you have GFCI receptacles at the load end of the run, I'd say any problem is with equipment that is plugged in and not with your wiring.

 

[goldstar]

I was not able to do that because I converted them over to surge protector type. So, I had to protect both circuits with GFCI breakers. This facility has a lot of power outages and brown outs. In addition they generally run hot during the summer and burn stuff up. They once burnt a 200 amp meter enclosure.

 

[kwired]

I was not able to do that because I converted them over to surge protector type. So, I had to protect both circuits with GFCI breakers. This facility has a lot of power outages and brown outs. In addition they generally run hot during the summer and burn stuff up. They once burnt a 200 amp meter enclosure.

So you have GFCI protecting 100 or so feet of circuit? That leaves you with a lot of possible capacitive leakage that could trip the GFCI.

 

[goldstar]

Sorry, I made a typo in the title. It should have read "Mixing GFCI circuits with non GFCI".

 

[goldstar]

So you have GFCI protecting 100 or so feet of circuit? That leaves you with a lot of possible capacitive leakage that could trip the GFCI.

Thanks. How do I go about testing for that ?

 

[kwired]

Sorry, I made a typo in the title. It should have read "Mixing GFCI circuits with non GFCI".

I eventually figured that out. But if you have a long GFCI protected circuit your chances of nuisance trips goes up because of (A) longer circuit has more potential places it can fault, (B) capacitive effects are greater for a longer run - you essentially have a larger capacitor so it will draw more current.

 

[norcal]

Could the GFCI circuit breakers be eliminated & put blank face GFCI's ahead of the surge protectors? Not knowing the details of the job, may mean this is not possible but may be worth a thought.

 

[goldstar]

A lot of work but yes it could be done

 

[iwire]

For what it is worth it sounds like you have more than one branch circuit running to a separate structure. That is an NEC violation.

You should really have a feeder to the pavilion with a panel there.

 

[goldstar]

For what it is worth it sounds like you have more than one branch circuit running to a separate structure. That is an NEC violation.

You should really have a feeder to the pavilion with a panel there.

There are several feeders with sub-panels in this pavilion. This particular panel one has two 20 amp branch circuits to the DJ area. # 12 THHN's leave the panel in 1/2" EMT to a JB and then in 3/4" EMT to the DJ area. I probably won't get back there until after 4:00 PM today to determine if there is a ground fault problem or not. I have a feeling that Kwired is probably correct in that it may be due to capacitive effects within the conduit. I'm hoping it's the DJ equipment so I don't have to take a hit on the chin for the CH GFCI breakers. It's bad enough that my time to trace this is likely to be pro bono.:weeping:

 

[RobertKLR]

I believe this has been discussed here in the Forum before but I don't remember what the answer was and I couldn't find it in the archives. I have a situation at a day camp where there is a DJ station inside an outdoor pavilion. I had recently converted (2) quad non GFCI receptacles on separate circuits to surge protector type and installed CH tan handle, 20 amp GFCI breakers. They are now experiencing intermittent tripping at the DJ station. I have not been back to investigate yet but I'm wondering if it may have something to do with the fact that both 20 amp GFCI circuits are in the same conduit as non GFCI circuits. Any opinions ? Thanks.

I would say no, the GFCIs trip because at least 6 milliamps of the current going out of the device is not returning therefore it must be going somewhere else. Meg the wires to eliminate them but most likely it's the customers equipment. I would look at their equipment and contact the manufacturer or distributer and get their input on using GFCIs with their products. I went through an episode with a Hoshikawa ice maker that would trip a GFCI often but the GFCI checked good every time. I called the maker and was told they do not recommend using a GFCI on their ice makers due to leakage current caused by moisture and contamination.

 

[iwire]

I called the maker and was told they do not recommend using a GFCI on their ice makers due to leakage caused by moisture and contamination,

Did you explain to them that the GFCI requirements are not concerned with their recommendations?

 

[goldstar]

Stopped by at the day camp today and found the following :

• Inspected the standard sound equipment and found no ground fault problems
• It seems that the only time problems arise is when the DJ come with his equipment and adds to the mix
• So, still not sure if it's an overload problem or a ground fault problem

There's a similar situation in the kitchen of the same pavilion. Before converting receptacles for ice cream freezers to the surge protector type one set of (2) freezers was plugged into a GFCI receptacle. They had never tripped the std. Siemens 20 amp breaker or the GFCI receptacle. I converted that receptacle to a surge protector type and changed the breaker to a Siemens 20 amp GFCI breaker. So far they've lost the ice cream in those freezers twice since I made the change. This circuit was run with 12 ga. NM cable. When I got there today one of the freezers was plugged into no-GFCI receptacle via an extension cord and running fine. The other was plugged into the GFCI protected surge protector receptacle. That GFCI breaker was tripped when I got there and the freezer down. I converted that breaker back to a std. 20 amp breaker and measured the current draw and it was about 6 amps. The only thing I can guess is that this particular freezer developes a ground fault problem sometime after it is running awhile. Only time will tell. I'll go back saturday morning and re-test. Thanks for all the input.

 

[iwire]

Don't surge suppressors connect neutral and hot to ground via MOVs?

 

[goldstar]

Don't surge suppressors connect neutral and hot to ground via MOVs?

I believe they do but my basic understanding is that it will only bleed off to ground in a power surge condition. If they were tied together permanently the circuits would not have worked from the start.

 

[hbiss]

Yes, it's the surge protectors. Been discussed here before. I have seen many instances where surge protectors trip GFCI receptacles. Apparently there are instantaneous spikes high enough to cause the MOVs to limit them and conduct to ground. Either eliminate the protectors or put them ahead of the GFCIs.

-Hal

 

[goldstar]

Yes, it's the surge protectors. I have seen many instances where surge protectors trip GFCI receptacles. Apparently there are instantaneous spikes high enough to cause the MOVs to limit them and conduct to ground.

-Hal

That's a good point. This facility is subject to numerous power outages, brown-outs and voltage spikes. What I'm having difficulty with is why some areas work fine while others have nuisance trips. FWIW, I've used a cascaded approach to providing surge protection at this facility. The surge protector receptacles in both the ice cream freezer area and the DJ area are fed from a 120/240 V Delta 3-phase breaker panel (not sure why - it was done that way before I acquired this project) or from a sub-panel off that main lug panel. There is also a single phase 120/208 panel in this pavilion and both main lug panels have surge protection installed at the head end. So, if any power surge is getting through it must first pass the surge protectors at the head end. In all cases the surge protector receptacles are fed off the load side of the GFCI protection.

BTW, I appreciate all the information and opinions so far. I have a tendency to not think "out of the box" at times and a lot of what has been discussed here to date makes a lot of sense. Just thinking out loud - I may try moving those two circuits out of the 120/240 V panel and into the 120/208 V panel and see if that changes anything. My reasoning is that there are 4 swimming pools (and about ten 3-phase motors) and a lake with a 3-phase aerator motor in its center at this facility. All are fed by the same 120/240 POCO transformers via the distribution panel in the admin building. It could be that if there is a split second power outage those motors could cause a spike and be part of the problem. Too many "ifs" and I don't have the time to diagnose with kids in the camp.