Electric junction box making buzzing noise


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Old 07-03-18, 06:12 PM
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Electric junction box making buzzing noise

Hi, I have a junction box kind of thing in my basement, see attached picture. looks like it is just redistribute the power. there used to be a smoke detector under it which I removed already, thats why you see the cap with two power lines. Recently it starts to make those buzzing noise almost constantly - anyone might know what is causing the noise? I see there are 4 squared unit outside that box to the right. Not sure whether the noise are coming from there. I don't know what are those, any idea what I can do to get it fix? Thanks, bluebottle66
 
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Old 07-03-18, 06:31 PM
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The noise is coming from the two transformers mounted to the side of the box. Transformers hum, it is just a fact of life.
 
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Old 07-03-18, 08:35 PM
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Those are some hefty transformers. That gray wiring to them almost suggests home entertainment equipment or an intercom system.

They could possibly be for the heating system too if you have zone valves on a hot water boiler.
 
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Old 07-04-18, 08:32 AM
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Thanks for all the response! My house is rather old and it does has a very old half-working intercom system and home security system, so I guess the two grey lines are indeed for that.

Since it is starting to make much louder noise than in the past, does that mean the transformer might be close to end of their life? Any concerns for me and shall I try replace those? Feel like it might not be cheap...
 

Last edited by bluebottle66; 07-04-18 at 08:37 AM. Reason: wrong description
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Old 07-04-18, 08:41 AM
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Those transformers convert 120v to 12-24vac. The exact value should be listed on it. A typical size is 16.5vac.

Those are old school transformers. They should last a lifetime. You can buy brand new transformers that also hum. The hum is no indication of its condition. They would cost approx $20-35 each to replace.
 
 

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