What is this?

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Dennis Alwon

Dennis Alwon

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Chapel Hill, NC
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Retired Electrical Contractor
Take note of the electronic unit that is wire to both busses. What is it and is it legal?? This is an old Sq. D panel with 200 amp Main Fuses and breakers below.

47b8dd10b3127cceb793902b183600000026100UaNmbRs1Ys





47b8dd10b3127cceb7939015180800000026100UaNmbRs1Ys
 
Looks like either a disk capacitor or, more likely, a MOV (Metal Oxide Varister). MOV's are used to suppress voltage transients. Hard to tell by looking.
 
Is that for X10 or something similar?

Is that for X10 or something similar?

What do they call it when devices can signal each other over the powerline?

Could be for lighting controls or even some voice/data application.

In anycase, I'll bet its not a powerfactor correction cap.

Looks like something a sophisticated HAM homeowner would do, that knows electronics real well, but not the NEC.

http://en.wikipedia.org/wiki/Power_line_communication
 
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sgunsel said:
Looks like either a disk capacitor or, more likely, a MOV (Metal Oxide Varister). MOV's are used to suppress voltage transients. Hard to tell by looking.
Click to expand...

That was my guess that it was some surge suppressor but I really had no idea--total guess.
 
Dennis, did you check the torque on those 2 bolts? Seems to me that if properly torqued they would bite right through the 2 little wires.
 
480sparky said:
I'll vote for a DIY MOV myself. And I'll add that it's not legal.
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I would also bet it is a MOV. I suspect it is not legal to install it there, but I am not 100% sure of that.

It might also be a capacitor. Sometimes other people can be on the same utility transformer and RF generated downstream can show up on anyone on the same transformer. I seem to even recall that the X10 people even recommend such a setup at one time in case you are getting interference from a neighbor's X10 system.
 
Then again, if it is a home-made MOV, it's only protecting line-to-line. No line-to-ground, line-to-neutral or neutral-to-ground protection at all.
 
Dennis Alwon said:
Take note of the electronic unit that is wire to both busses. What is it and is it legal?? This is an old Sq. D panel with 200 amp Main Fuses and breakers below.

47b8dd10b3127cceb793902b183600000026100UaNmbRs1Ys
Click to expand...

Yep, it is legal as long as your state has no ordnances against firecrackers.:D

It's an MOV(Metal Oxide Varistor) that is often used to absorb overvoltages and dissipate the I2T energy by converting it to heat.

Would be more useful to connect it between phase(s) and ground.

Since it is a component and not likely approved for the purpose, it most likely constitutes a modification violation of the panel.

It has solid wire legs, so even if the bolts are properly torqued, it would only slightly deform the single wire, not unlie the individual strands of a multistrand cable would do so.

It's one for the books......:grin: of How and What Not To.....
 
You all are just too dang smart for me...:smile: I am still trying to remember what MOV stands for-- I keep forgetting the V part-- varister. I might add I never even heard of it. Oh dopey me.:smile: Oh yeah and thanks for all the replies.


Chris--- I ain't torquing nothing. I was happy to get out of there. 30 circuit panel with 35 circuits and he wanted me to add more. Handy installed a makeshift kitchen and they have one receptacle (GFCI--surprised by that)-- for the toaster , MV and bread maker. They wondered why it was blowing the circuit.
 
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weressl said:
Varistor is stands for Variable Resistor to indicate that the device's resistance varies with the applied voltage. Now it maybe easier to remember:) .
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Thanks, but now I will want to call it a MOVR. :grin:
 
was by chance the owner of this house a ham radio operator?
This could be a capacaitor installed to filter out noise in the ac for his radio equipment or as the other post a MOV
 
nolangro said:
was by chance the owner of this house a ham radio operator?
This could be a capacaitor installed to filter out noise in the ac for his radio equipment or as the other post a MOV
Click to expand...

Not this homeowner but could have been a previous HO.
 
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