Lightning and main breaker

[zapped 1]

i have a 3 phase 200 main breaker for parking lot lites on the back of a grocery store, other day main was tripped reset fine and held for over 3 hrs,afternoon and evening storms roll thru with alot of lightning and breaker has been tripped twice now after big storms. Could lightning affect main,took amp draw readings and physically checked all j boxes associated with lites . i understand there could be something with the system itself but is it possible for lightning to affect the operation of the main breaker.

 

[hillbilly1]

Is this a 480 volt system? If so the wiring is probably damaged underground and causing a ground fault. The magnetic trip settings on the main are probably set to the lowest position which can make it trip faster than the smaller breakers. Probably need to megger the runs and find out which one(s) are the culprit.

 

[zapped 1]

120/208

 

[Hv&Lv]

i have a 3 phase 200 main breaker for parking lot lites on the back of a grocery store, other day main was tripped reset fine and held for over 3 hrs,afternoon and evening storms roll thru with alot of lightning and breaker has been tripped twice now after big storms. Could lightning affect main,took amp draw readings and physically checked all j boxes associated with lites . i understand there could be something with the system itself but is it possible for lightning to affect the operation of the main breaker.

Could also be a bad head on a light. I assume the lights are on a photocontrol, then to a relay. The storms could be a coincidence. It could be getting dark enough for the lights to come on, short out in the head, and trip the main. Tape over the photo control and see if the main trips in the daytime.

 

[hillbilly1]

Could also be a failed surge suppressor on the poco's end allowing surges to get thru. My neighbor kept getting hit with surges every time it stormed because the line split in front of his house, and headed up a mountain. I could physically see the protector burnt on the pole, called the poco, they came out and replaced it, he had no more problems.

 

[templdl]

Could also be a bad head on a light. I assume the lights are on a photocontrol, then to a relay. The storms could be a coincidence. It could be getting dark enough for the lights to come on, short out in the head, and trip the main. Tape over the photo control and see if the main trips in the daytime.

I ditto Hv&Lv and hillbilly1 suggestions. A HV lightning surge very possible found a weak point in the insulation somewhere and/or a component that broke it down resulting in the breaker instantaneously tripping as hillbilly1 pointed out. He also pointed out the possibility that if it is a larger frame breaker the mag. setting may have been left set in the as su[pplied factory setting which is 50% of the max. But, even so to reset it high would be putting a band aid on a failure if you are able to get the breaker stay closed.

 

[zapped 1]

we will be replacing repairing heads tomorrow any suggestions beside adding a surge protector at the panel. we will also have poco check there end. during the day we have bypassed photo eye and there have been no problems.

 

[templdl]

we will be replacing repairing heads tomorrow any suggestions beside adding a surge protector at the panel. we will also have poco check there end. during the day we have bypassed photo eye and there have been no problems.

It has been of my belief that lightning arrestors or surge protection does add some degree of protection but it certainly does not guarantee it.

 

[hillbilly1]

Does it only trip during storms now? Or is it tripping regularly? If only during storms, then it may be the surge theory. If regularly, probably a ballast issue, I haven't had insulation breakdown a main tripping issue at 208 volts, at that voltage it's usually the branch circuit tripping.

 

[templdl]

I always overlooked the type of trip unit in the breaker that you have. Being 200a, if it has the older variety electronic trip unit it is very likely that it is peak sensing and not RMS sensing. RMS sensing technology wasn't available when the original electronic trips can out as such they are more opt to trip because of a voltage spike cause by lightning, PFC capacitor backs switching, or other disturbances that can case voltage spikes. This is probably not going to be the issue but should be eliminated as a possible cause.
But, my assumtion is that you have a common standard TM trip unit.

 

[zapped 1]

it oniy trips during storms at this point. does it have anything to do with magnetic fields possibly ,i do not have alot of knowledge about this area

 

[hillbilly1]

it oniy trips during storms at this point. does it have anything to do with magnetic fields possibly ,i do not have alot of knowledge about this area

That's why I think it may be a surge comming in through the utility, either that, or maybe your grounding electrode system has been damaged by a close or direct strike. Is the grocery store on the same transformer? Are they having any voltage problems?

 

[meternerd]

i have a 3 phase 200 main breaker for parking lot lites on the back of a grocery store, other day main was tripped reset fine and held for over 3 hrs,afternoon and evening storms roll thru with alot of lightning and breaker has been tripped twice now after big storms. Could lightning affect main,took amp draw readings and physically checked all j boxes associated with lites . i understand there could be something with the system itself but is it possible for lightning to affect the operation of the main breaker.

Probably not available to most except utilities, but if you can borrow a digital recorder, you can see a graph of loads and events prior to tripping. Your utility may be willing to set one up at your service panel to see what your loads look like. Another possibility is that the breaker is defective. Most breakers have a latching device which releases the latch keeping the breaker contacts closed when a trip level is present. Frequent tripping can "round off" the edge of the latch and keep the breaker from staying closed when carrying normal amouts of current. Often they won't even reset after a trip.

 

[templdl]

I may have missed it but what is the breaker and the type of trip unit? Was the breaker ruled out as a possible cause?

If it's a common non-electronic TM breaker then it most likely can be ruled out as a possible cause of the problem. However, you may want to assure that if the mag adjustment isn't set in the highest setting there is no reason or standard that wouldn't allow you to do so.
If it's an older technology peak sensing electronic trip it should considered as being a potential cause of the nuisance trips and then ruled out as being a cause. The newer electronic trips a RMS sensing an much less sensitive to line disturbances. Sometimes the obvious can be easily overlooked. I have had a 400a breaker with an old school peak sensing electronic trip that trip almost religiously at 5:00AM knocking out a sewerage lift station. Someone would have to go there an reset the breaker and everything was fine the rest of the day. The management of the district were not happy campers. I was invited to a very sensitive meeting where the people weren't happy campers. I agreed to make the problem go away with the hope that they wouldn't be hitting be with back charges for their time.
I gave my customer a brand new replacement breaker that had the old school none electronic TM trip unit at no charge to replace the existing breaker. They installed it and the problem went away.
Since the breaker tripped at close to the same time I concluded that there must have been a PFC bank that was switching causing a voltage spike. Voltage spike resulted in a current spike which the peak sensing trip unit was responding to. I could have place a recorder on the system and wasted time trying to record the event but it wasn't worth the continued trips.