Noise at the service drop

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Does someone have heard about noise at the service drop in USA?

Here in Qu?bec we have few hundred cases in the province.

Typically, on a cold winter night when the electrical demand is high, the transformer noise seem to be amplified by the utility Cie (Hydro-Qu?bec) triplex wich is fixed to the mast or the house with the spool rack.

The tranformer noise is so amplified so we can hear the transformer humming in the house. It's worst in a 2 story house when to spool rack is fixed on the wall were the bedroom is. Some people can't sleep because of the noise.

Some contractor even Hydro-Qu?bec have replace the spool rack isolator with a ruber isolator to try to stop that without result.

In often happen in house with a big electrical furnace.

Sometime Utility Cie says the house is not properlly built....The way house are built did not change in the last years....
 
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PetrosA

Senior Member
I have heard heavily loaded feeders hum, but they were in a trough. It could have been the cables or the connectors used to tap off of them, I'm not sure. I can't imagine that you're dealing with vibration from the transformer since the triplex is not attached to it but to the pole. I would rather suspect that the vibration is coming from heavily loaded triplex or connectors rather than anything at the pole.
 

kwired

Electron manager
Location
NE Nebraska
How tightly strung is the service drop? A little sag here could prevent less vibration transmission, plus you have two other factors going against you - higher load because of cold weather, contraction of service drop because of cold weather - making it tighter then when it is warmer.
 
How tightly strung is the service drop? A little sag here could prevent less vibration transmission, plus you have two other factors going against you - higher load because of cold weather, contraction of service drop because of cold weather - making it tighter then when it is warmer.

The service drop is pretty tight. Today i heard from a home owner that the hum could be cycled. 3-4 second on, 3-4 second off. His house is with 5 other house on the same 50kVA transfomer.
 
How tightly strung is the service drop? A little sag here could prevent less vibration transmission, plus you have two other factors going against you - higher load because of cold weather, contraction of service drop because of cold weather - making it tighter then when it is warmer.

I have heard heavily loaded feeders hum, but they were in a trough. It could have been the cables or the connectors used to tap off of them, I'm not sure. I can't imagine that you're dealing with vibration from the transformer since the triplex is not attached to it but to the pole. I would rather suspect that the vibration is coming from heavily loaded triplex or connectors rather than anything at the pole.

Thanks, your right about the transformer.
 
Location
MA
Some transformers will vibrate enough to feel it by hand at the bottom of a pole and definitely at the end of a service. You can feel it on a service some times, but you can't hear it. I would imagine that it's very possible for someone sleeping in the room next to the service attachment to feel/hear it. Adding more slack may help, like mentioned, but I don't know how much. Some brands of transformers hum more than others, maybe changing it out if it's old will help. We get humming transformer calls all the time and there's pretty much nothing you can do about it unless it's 30 years old and you replace it, which may not do anything.
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
it could even be transmitting from the transformer, down the pole, through the ground and into the walls, but the residents make PERCEIVE that it is coming from the weather-head because that's what they can see. I have a utility substation about 250 yards away from me on the other side of a creek, but under the right circumstances I can hear and feel the transformer hum coming up from the ground.

It is what it is, I'd rather have that than no electricity...
 
Some transformers will vibrate enough to feel it by hand at the bottom of a pole and definitely at the end of a service. You can feel it on a service some times, but you can't hear it. I would imagine that it's very possible for someone sleeping in the room next to the service attachment to feel/hear it. Adding more slack may help, like mentioned, but I don't know how much. Some brands of transformers hum more than others, maybe changing it out if it's old will help. We get humming transformer calls all the time and there's pretty much nothing you can do about it unless it's 30 years old and you replace it, which may not do anything.

Pole transformers are supplied by the utility cie (Hydro-Qu?bec). It happen with brand new transformer on new streets with new houses. A contrator try a lot of thing, a the end he installed a wood pole near the house. Triplex was fixed to that pole with the socket meter on it and a undergroud conduit run from the socket meter to the house electrical panel board. Noise stop because triplex was fixed to the pole instead of beeing fixed to the house. Sometime humming come from the neighbour houses. often humming start and stop with the house electrical furnace....Sometime i think Hydro Qu?bec triplex and transformer could be sized to tight. Other think it's start with a new generation of transformer..... Its really hard to put the finger on what cause the humming.
 
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