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	Subject - lights flickering while using electric range abusi In the 6 months I have been in my new house I have become accustomed to the lights breifly dimming as the heat pump, heat pump aux heat, well pump, & dryer are switched on. This weekend while using the electric range I noticed that the lights are dimming breifly as the burner elements cycle on & off. Concerned that there might be a loose connection in the panel causing this I checked the panel & confirmed that all connections are tight & all the breakers are seated firmly. I re-seated the breaker for the range & the stabs & contacts on the breaker were in good condition. I proceeded to turn the power back on & run the stove while listening at the pannel for any arcing & sure enough when the burners cycle on there is a brief buzz sound comming from the panel. I also noticed that when the heat pump cycles on the panel makes the same brief buzz. The house is six months old with a 200 amp service & has an outside Murray/Siemens service disconnect. The main panel inside is a Cutler-Hammer 40 space BR series with a copper bus. The feeder wire is aluminum 4 wire with the ground and neutral bonded inside the panel. I am unable to dermine if the brief buzz sound when the stove or heatpump cuts on is comming from inside the breakers, the connection between the bus bars and the breakers, or from the main breaker. The buzz sound is very faint lasting less than a second even with the cover off the panel but, it is my understanding that any noise comming from the panel is abnormal. My suspicion is that the buzz as these loads come on is comming from the main breaker. There is no buzz while the loads are on, only when they first come on. The main breaker is a Cutler-Hammer BW2200. Is any amount of noise from the panel normal? Any suggestions on what else I could check? I plan on having an electricion who works where I work take a look at my panel as soon as he can. Thanks for any advice or suggestions. Aaron kbsparky You may indeed have a bad main breaker. You might want to contact the folks at Cutler Hammer, and inquire about whether brief buzzing coming from the main is a normal thing or not. Get them to admit that their breakers should not buzz, or something like that As for the brief flickering of your lights, this may be related to that breaker, and/or you could have an outside loose connection, or undersized utility transformer. We had one instance where the customer complained about the same thing, and discovered that their transformer was only a 5 kVA!! Seems that they used to live in a single-wide mobile home, with gas everything, and then bought a new all electric double-wide, and connected to the same source. The utility company had to come out and change that pot to a 15 or 25 kVA (not sure which one they used, but it was substantially larger than the old one) nfsus You have a 200a service with #4 al running the load? Or is it 4/0? I have found that if all heavy loads cause a buzz then it is not a single breaker causing this. The first thing that I would di is check how tight the lugs are. Where they bolt onto the buss and how tight the screws are where the aluminum wire lands. stedder Could be loose connections anywhere on the main busses even at the meter (if the meter lugs are loose the power loss / arcing may cause the loaded breakers to strain) abusi Thanks to all for your replies. I believe that the transformer is a 15kVA as it has the number 15 on it. The wire between the outside electric service disconnect and inside panel is 4/0 al cable. The aluminum cable does have antioxidant applied at the main lug connections & the lugs on the main breaker on the inside panel seemed to be tight. I have not opened the outside Murray/Siemens service disconnect panel containing a 200 amp breaker as I am not comfortable working around live equipment. I spoke with an electrician who works for the college where I work and he thinks there is probably a loose connection somehwere possibly outside the house in the service disconnect or the meter base. He is going to come by my house hopefully this weekend & will check everything. If we have to pull the meter do I have to notify the utility or will they simply "re-seal" the meter? My utility is Dominion VA Power. My house has a one year "warranty" from the builder but I am hesitant to have the builder send out the "electrician" who wired the house as the first day I was in the house one of the lighting circuits kept triping a breaker & I tracked down the fault to a pinched wire in my hall light where they had wraped the excess wire around a metal bracket in the box causing the wire to be pinched & shorted to ground. I have since checked every electrical box in the house & corrected several other possible hazards including several splices where they had stripped way too much wire leaving the hot exposed & nearly touching the ground wire (this gem was in a box feeding a smoke detector). The "electrician" also did not install any AFCI's on the bedroom circuits. The only thing I trusted the builders electrician to fix was to put on the cap they had left off the top of the outside service disconnect panel (they had the hole covered with electrical tape). For these reasons I will not let the fool who wired the house near it again. Sorry for the long rant but I figured I'd give some more background to the electrical at my house. Aaron nfsus Abusi- do you live near Mt. Home, Arkansas by chance? Or know a Rob Williams? It sounds alot like a job I saw while working for my former employer. But then again, I guess wrong can be done the same no matter where it is. abusi nfsus- I live in Farmville, VA. Aaron kbsparky Have you called Old Dominion? I believe they are a coop utility. They should come out and check their connections for free abusi My electrician friend from work came by my house today & he checked everything out. He confirmed that I had properly checked everything in my main panel & torqued the main lugs on the main breaker & tightened the bolts connecting the main breaker to the bus bars. He said everything seemed reasonably tight but he was able to tighten things up a little bit. He also confirmed that I was correct in my assumption that the electrician who installed the panel had improperly left the bonding strap in place so he removed the strap isolating the ground bar from the neutral. The ground and neutral are bonded through the case of the outside service disconnect panel. He said that in the disconnect panel I should probably add a no 6 conductor directly between the terminal block where the inside ground cable and ground rod are attatched to each other & connect that block to the neutral bar so there will be a better bond than just using the case of the disconnect panel. Everything was tight in the outside disconnect panel. Having done all this there is slightly less dimming of the lights when large loads come on. I powered almost everything on & he checked the load & voltages & said everything looked good with no unusual fluctuations. He basically gave my panels a clean bill of health & said he does not think the level of flicker is anything to worry about though he admits it is a bit more than you would expect with a 200 amp service. So I guess I'll stop worrying. Thanks to everyone for their repiles to my post. This is a great site! Aaron