TVSS Double lugging

[magictolight.com]

Went on a call today to a good client who wants to install some transient voltage surge suppression. He wanted me there to listen to a sales guy talk about some product that will gaurentee him 15% reduction in his electric bills. Anyway this sales guy tells me that when a panel is full his electricians will usually double lug the tvss conductors under an existing breaker that is already supplying another circuit. I tell this guy there is no way those breakers, 3 phase 240 volt QO breakers are UL rated to do what he is telling me to do. He says that his guys never cobble and I am just wondering if I am loosing my mind? Is this an acceptable installation? That is, one circuit breaker feeding a load and the TVSS unit, with two conductors under one lug? I don't think and of course these panels are 3 phase and all the way full.

 

[Jim W in Tampa]

He is a salesman that has no clue about NEC NE what ? While often over looked on service , there is no legal way to double lug most breakers. Could pig tail and splice. Don't hold your breath while waiting on that 15 % savings . Get it in writing and don't pay him till you see it. SCAM big time

 

[goldstar]

If circuit breakers have a clamp-down, pressure plate type of termination then two wires can be installed on either side of the screw as long as the wires are the same size. But you can't use a 60 amp breaker where a #6 wire is installed and held in by only a screw and then jam a # 12 in with it. For the same reason you can't jam a wire into the lugs alongside a service conductor.

 

[jackcc007]

If circuit breakers have a clamp-down, pressure plate type of termination then two wires can be installed on either side of the screw as long as the wires are the same size. But you can't use a 60 amp breaker where a #6 wire is installed and held in by only a screw and then jam a # 12 in with it. For the same reason you can't jam a wire into the lugs alongside a service conductor.

Goldstar. I too, was asked about this type of TVSS installation practice. am familiar with the type of breaker that you referenced. I was curious, though, where in the NEC might this issue be addressed. For example, if I were to quote the NEC as condoning this type of TVSS installation, would I refer to section 210.4 (Multiwire Branch Circuits), or somewhere else?

 

[don_resqcapt19]

Goldstar. I too, was asked about this type of TVSS installation practice. am familiar with the type of breaker that you referenced. I was curious, though, where in the NEC might this issue be addressed. For example, if I were to quote the NEC as condoning this type of TVSS installation, would I refer to section 210.4 (Multiwire Branch Circuits), or somewhere else?

You would refer to 110.14(A) that says you can't land two wires on a terminal unless it identified for such use.
The fact that the terminal appears to be suitable for use with more than one conductor does not mean that it is.

 

[don_resqcapt19]

Went on a call today to a good client who wants to install some transient voltage surge suppression. He wanted me there to listen to a sales guy talk about some product that will gaurentee him 15% reduction in his electric bills. Anyway this sales guy tells me that when a panel is full his electricians will usually double lug the tvss conductors under an existing breaker that is already supplying another circuit. I tell this guy there is no way those breakers, 3 phase 240 volt QO breakers are UL rated to do what he is telling me to do. He says that his guys never cobble and I am just wondering if I am loosing my mind? Is this an acceptable installation? That is, one circuit breaker feeding a load and the TVSS unit, with two conductors under one lug? I don't think and of course these panels are 3 phase and all the way full.

QO breakers in sizes 10 amps through 30 amps are suitable for use with two conductors. Larger QO breakers are only suitable for use with single conductors.

 

[ike5547]

How does TVSS protection reduce your energy bill by 15%? I think I would have focused on that BS first.

As for doubling up on a breaker, you can just make a splice in the panel instead.

 

[ohmhead]

How does TVSS protection reduce your energy bill by 15%? I think I would have focused on that BS first.

As for doubling up on a breaker, you can just make a splice in the panel instead.

Well they dont !

In fact they use power to work in circuit heres how they work .

Its kinda like a diode in simple terms its a MOV metal qxide varistor which has been around for manys years but now they call them TVSS
sounds more important .

TVSS transit voltage surge suppressors but its a basic MOV or multipule combinations of mov s depends on voltage they actually use a small amount of power to just work online at your voltage by there nature of being a diode kinda .

There internal resistance is high at rated voltage but at a higher voltage meaning a voltage spike they conduct and pass current and limit the spike meaning they keep the voltage at set normal level .

But they are using power so its not saving anyone energy if you feel them there warm to the touch thats wasted power .
They have a tiny reverse current all the time when in normal use.

Tell your sales rep to come on this forum and will debate with him .

Ask him how long they last in real time most think there ok and if no large surge hits they are good for years but they break down during normal use and age you dont need a major surge to break down a tvss if you have lots of voltage spikes they can go bad into days electrical demanding world thats a normal issue .

But thats just my thoughts and iam just a simple electrician who just runs conduit underground all day .