panel making "LOUD" hum

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acrwc10

acrwc10

Master Code Professional
Location
CA
Occupation
Building inspector
I got a call that when the home owner turns on some electric heaters , mounted on a patio, that there is a bad hum comming from the panel.
Correct me if I am misstaken but I don't believe this is "code compliant" :mad: contactor gone bad and is just screaming.
See any code violations ?


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In the first image there are no NM connectors on the right side of the panel. I would also question if the panel is listed to have that relay(?) installed on the right side.

The second image is a nightmare and looks overfilled IMO.
 
Pic 1) Wheres the main breaker? The lugs look as if they were installed in the field. Is this a service panel or a sub panel? Where are the panel mounting screws. None in the back for sure. Missing NM connector right side. Whats up with the SE cable. The jacket is not a conductor. Where is the braided bare Neutral/Ground wire landed. I guess they could'nt get the relay in Pic #2.

Pic 2) Top contactor crooked. Full for sure, but may not be a violation. Again I see no mounting screws. Locknut missing on bottom connector. I have seen worse jobs. But see little wrong with number 2. Easily corrected.
 
What's the deal with the 12/3 cable? I think I understand how the 12/2 is being used, not clear on this one.

I'm not aware of any clamp connectors listed for use with 4 x 12/2 cables (upper right, 2nd picture). Hopefully there is a ground lug of some kind back behind all those wires, even then, it's seems to me a single lug would not be suitable in this application.
 
I don't see a bushing for the NM cable coming in from the right of the breaker panel. Also, it appears a tied breaker on the upper left has one leg that is double tapped.

The noise is likely a bad contactor, but I question the power contactors as they are for 3-phase system and the heating coils may also be 3 phase but all of it has apparently been modified for 240. Which makes me wonder more about the double tapped leg and the effect of balance between the legs and pressure on the neutral.

Finally, if this is all on a patio... that is likely a damp or wet location... I don't recognize the control relay as a GFCI.
 
John Valdes said:
Pic 1) Wheres the main breaker? The lugs look as if they were installed in the field. Is this a service panel or a sub panel? Where are the panel mounting screws. None in the back for sure. Missing NM connector right side. Whats up with the SE cable. The jacket is not a conductor. Where is the braided bare Neutral/Ground wire landed. I guess they could'nt get the relay in Pic #2.

Pic 2) Top contactor crooked. Full for sure, but may not be a violation. Again I see no mounting screws. Locknut missing on bottom connector. I have seen worse jobs. But see little wrong with number 2. Easily corrected.
Click to expand...


pretty sure this is a sub-panel; homeline's have convertible mains, which means you can easily snatch the mb out and put lugs in. honestly it probably came w/ the lugs because a 12 space homeline w/ a mb installed from the factory is a rare find. the mounting screws are in the side, which is where i always put mine as the drywall behind it probably wouldn't do a good job of holding it up. :D the bare conductor is going to the ground bar that you can't see in the pic, but is obviously there because all the grounds are going to that side.
 
a few minor violations. nothing to get real worked up over.

not sure the contactor is allowed or not in the PB or not. I was unable to find any prohibition against mounting such a device in the PB, so I am thinking it is acceptable.
 
Not the prettiest of work - a few violations in NM entrys. Would have been done better with a nipple between the two enclosures and the right one could be 2-3X larger.

And could you define 'loud'... Relays will hum....

Now the big question - why do these people have electric heat on the patio?
 
I've had a couple instances here with angry humming from patio heater relays. They've all been instances of under-voltage on the control side - usually ~12VAC instead of the required 24VAC. Replaced supply transformers and all was good. Ours are set up with a digital timer, so they run for 30 minutes each time the doorbell switch is pressed.
 
e57 said:
And could you define 'loud'... Relays will hum....
Click to expand...

If they just bought the house and are using it for the first time, very true. In office panels, vs plant floor applications, I use either solid state relays or DC coils to eliminate the hum.

The the later comment on wrong voltage ... yeah, and burned out coils, too. In my side of things (industrial), the coil would cost less than a transformer to change control circuit voltage.
 
Yikes..!!
Looking beyond things like connector and KO issues, I can?t read the labels on those relays, are they general-purpose relays or lighting contactors?
Are they designed and rated to handle resistive heating loads that high?
I see possible 312.5, 312.6, 312.7, 312.8, 312.11 and 314.28 wire bending space door clearance and cabinet/box fill issues.
Also, shouldn?t they be mounted in an enclosure designed for the purpose? 110.3.
Looks like maybe all the equipment grounds are stuffed into one lug too, 110.14[A].
 
For what it's worth, I've quieted loud contactors by lubricating the pivot of the armature, so it meets the pole face more squarely.



Added: Edited for lousy spelling.
 
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loud is LOUD

loud is LOUD

I may have under stated loud, when I was in the room where the panel is we could not talk with out yelling. I would compare it to an older stile door buzzer.
I have not had the chance to do more then turn off the panel and I will be T shooting it next week, although I know the noise is the contactor in the homeline panel.
And yes they are electric heaters about 12 of them , I guess gas heaters aren't loud enough :grin:
By the way e57 this is Atherton , thats why.
 
I stood on a deck for ten minutes today and was sweating! (First nice day in quite some time) But its not that cold here.... (Or Atherton for that matter) But they obviously have enough money to heat the great outdoors with the most expensive method - then the have enough for that to be done in a much better method.

FYI I only recently found out about CA T-24 limiting electric heat - they made no mention of outside ;) :rolleyes: (As "Patio" means OUTSIDE - right?)

And are these 'heaters' Nema 3? :grin: Fed by NM....

My solution would be to abandon in place - hire a good brick layer, and a plumber to do a quasi hydronic heat deal under the patio. Then stop by here to get a regular delivery set up... (My favorite place in the whole Bay Area BTW - Due to its rustic flavor and giant birds nest inside - seriously biggest birds nest I have ever seen....)

Here's my idea....
  • Gas ignited wood fired fan forced BBQ/boiler
  • Hydronic heat under the patio from said boiler (Just like the Romans... :wink: Frank Lloyd Wright would be proud!)
  • And heat the hot tub too.
IMO its great - who doesn't like a fragrant 1500F mesquite fire to keep warm or cook by, with hot rocks under foot, with a scalding hot tub to really exfoliate the senses with. :grin: 1/2 tempted do do it myself!!!! Since its Atherton they can just burn the currency of choice for the same effect... :grin:

(And I also assume there was no inspection on the install as is? I think we have disgusted the Inspectors there before)
 
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acrwc10 said:
I may have under stated loud, when I was in the room where the panel is we could not talk with out yelling. I would compare it to an older stile door buzzer.
I have not had the chance to do more then turn off the panel and I will be T shooting it next week, although I know the noise is the contactor in the homeline panel.
And yes they are electric heaters about 12 of them , I guess gas heaters aren't loud enough :grin:
By the way e57 this is Atherton , thats why.
Click to expand...

It sounds like your contactor is not "pulling in" or "seating" correctly. You can check for this by pushing against the moving assembly with a screw driver to. If there is rust on the steel parts of the contactor (the magnet assembly pole faces) it will not seal in completly and can really scream. This is similar to the post by LarryFine. While it might be possible to clean up the rust and dirt, it will continue to fail on a more frequent basis.

Another possiblity is that the copper shading coil in the fixed magnet assembly is broken or loose, again time to replace the contactor.
 
So I finally had the chance to repair this mess and what I found is this ;
1)Sq D Homeline panel with contactor installed in it, 110.3 (B)
2) 20/20 quad breaker has two 240 volt loads connected to it and only one has a common trip handle tie, 225.33(B)
3) 12-2 NM in lower right of panel has no box connector on ,
4) 12-2 running to contactor has only single conductor being used, neutral for this contactor is connected to buss , 300.3(B)
5) 4 or more NM cables entering box through one connector, 110.3(B)
6) 12x12 enclosure filled over 40% ,312.8
7) ground bar installed with sheet metal screws, 250.8
8) 11 ground wires under one lug, 110.3(B) & 408.41
9) ground lead cut off in 12-2 NM feeding contactor in panel , 300.3 (B) & ?

The 12-3 coming into the upper left in pic #2 has all 3 wires being used as incoming switch legs , I believe this is a violation of 300.3(B) also.

If there are any other issues you guys see or if I have called out something incorrectly please fill in the blanks for me. Thank you :)

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And just to be cute how about 110.12 :grin:
 
A little insight , the contactors are 4 pole contactors that are switching both leads on 7, 240volt loads 2 per contactor.
 
I'm glad I didn't have to solve this one.

To make a noise, something must be vibrating. I would have used a short garden hose and a helper to pinpoint the source.

In retrospect, what exactly do you think was making this noise?
Maybe a wire carrying heavy current and hitting the panel surface? A loose wire in the winding of a magnetic circuit breaker?
 
langjahr@comcast.net said:
I'm glad I didn't have to solve this one.

To make a noise, something must be vibrating. I would have used a short garden hose and a helper to pinpoint the source.

In retrospect, what exactly do you think was making this noise?Maybe a wire carrying heavy current and hitting the panel surface? A loose wire in the winding of a magnetic circuit breaker?
Click to expand...


Sorry I should have started with that :rolleyes: the contactor that was in the HomeLine panel had a bad coil, My guess is because of the heat the got generated in the panel. So I removed the contactor from the panel and also the leads that had no connectors on them,then I connected the loads up to the other contactors in the 12x12 box. Since the panel is right of the contactors I felt the disconnecting means was already taken care of so I used the contactors to only open 1 lead on each of the 240 loads, doing this made the contactors able to control 12 loads rather then 6.
There was one other interesting thing in all this the "electrician" had used rubber washers from a garden hose as bushings to mount the contactors on, if you look in the second picture on the bottom of the upper contactor you can see a little red piece of one.
 
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