Wire in conduit making noise

[uwireme]

I have a customer that asked me to take a look at his problem. When his heat pump condenser outside turns on the circuit feeding the unit in the garage makes a fast buzz sound (like a short circuit sounds) then the wires sound like they hit the side of the conduit violently.

The unit is 220 volts min. of 34 amps as per the condenser nameplate
The circuit is about 100 feet long in EMT and flex with 2-#6 THHN and 1-#10ground on a 60 amp breaker.
The thing I don?t understand is that the condenser works fine and has been doing this for months.
I checked the capacitor in the unit and is fine.


Phil

 

[don_resqcapt19]

Phil,
That is not really uncommon. The high inrush current sets up a large magnetic field that causes the conductors to move within the raceway.

 

[mdshunk]

Sometimes if you just jerk them one way or the other in the conduit, the buzz will go away.

 

[drbond24]

Phil,
That is not really uncommon. The high inrush current sets up a large magnetic field that causes the conductors to move within the raceway.

Really? That's cool! I've never heard of the conductors actually moving.

Why would you want to stop something so cool?

 

[djcrzysounds@yahoo.com]

I have it in 5 parallel feeds. #8 for 5HP 3 Phase 208V Motors. Happens all the time, was worse til I upgraded their sub-panel.

 

[alfiesauce]

Sometimes you'll get a good whip sound with a high inrush current start of a big motor in a conduit that is really low fill.

 

[electricalperson]

this happens at a place i work at. sounds like a rattle for a split second then goes away. its nothing to be too concerned about

 

[peter d]

this happens at a place i work at.

McDonalds?

 

[iaov]

McDonalds?[/QUOTE Insensitive!!:smile:

 

[ce2two]

You'll need to install non vibrating conductors (ha ha ha hah) available no-where....

 

[drbond24]

You'll need to install non vibrating conductors (ha ha ha hah) available no-where....

Are you kidding? At the rate Southwire is cranking out new kinds of cable, we'll have anti-vibration next week. :smile: