Surge protector with N-G bond

Status
Not open for further replies.
J

Jim Cavanaugh

Member
Location
Cicero, NY
I have a customer (copier dealer) who puts a surge protector on each copier system they sell. Recently they began using a surge protector that incorporates a neutral to ground bond that is activated by a relay when power is applied. The TVSS does not contain a transformer. It is ETL listed. It is my belief that creating a N-G bond in a TVSS would be a violation of the NEC (and a very serious safety issue). The manufacturer contends that the ETL listing is proof that their device does not violate the NEC. Any opinions?
 
I was not aware that any testing agency routinely considered the NEC in their standards development. For the most part (vending machines are one noticeable exception) the NEC does not address the construction of devices.
 
Welcome to the fourm. Is the copier listed as a complete unit by ETL? It looks like they may be in violation of section 250.142 (B).
 
Thanks for the welcome. It looks like this forum is a great resource.

The copier is UL listed. The TVSS is ETL listed. UL refused to list the same TVSS so the manufacturer went to ETL and somehow got them to list it.
 
Sounds like the copy machine just plugs into the surge protector, so it doesn't really involve the copy machine company.

Are you sure the surge connects neutral and ground? How do you know? Is it possible it is only an AC connection (through a capacitor), or that its through some resistance?
 
dereckbc said:
The UL standard for TVSS is 1449. If the TVSS does not have this listing I would run, not walk away.
Click to expand...

But UL and ETL are both NRTL's. Why should I think UL is better than ETL?
 
Yes. That is correct. The copier plugs into the surge protector.

The TVSS manufacturer has confirmed that they bond neutral to ground via a relay. Isn't this pretty much the same as connecting neutral to ground at the receptacle?

The TVSS manufacturer is marketing the device as having the same common mode noise elimination as an isolation transformer at a fraction of the cost.
 
steve66 said:
But UL and ETL are both NRTL's. Why should I think UL is better than ETL?
Click to expand...
All of the testing labs have to list the equipment to a standard. Most of the adopted standards are UL standards, but that does not mean that only UL can list to them. In fact, for many items the only standard that you can list to is a UL standard.
 
Jim Cavanaugh said:
The TVSS manufacturer is marketing the device as having the same common mode noise elimination as an isolation transformer at a fraction of the cost.
Click to expand...
I don't buy it.
 
Jim Cavanaugh said:
The TVSS manufacturer is marketing the device as having the same common mode noise elimination as an isolation transformer at a fraction of the cost.
Click to expand...
And they are half correct at the expense of life safety but only to the N-G mode. It does ZERO, NATTA, ZIP, NOTHING for the L-G mode.
 
dereckbc said:
And they are half correct at the expense of life safety but only to the N-G mode. It does ZERO, NATTA, ZIP, NOTHING for the L-G mode.
Click to expand...

Thats what I was thinking too.

My guess is that someone (probably a salesperson type) gave an oversimplified description of the connection between neurtal and ground. It's proabaly connected through a resistor, or a cap., or some other component. I would bet it meets the UL standard (even though UL didn't do the testing.)
 
Jim Cavanaugh said:
I find it curious that UL would not list this particular TVSS product (citing safety concerns) but ETL did list it.
Click to expand...

It's not that UL wouldn't list it. The manufacturer of the surge suppressor probably didn't ask UL to list it.

To get UL to list something, you have to pay them a bunch of money. Then you wait and wait for them to do the testing. (I think UL has become a big corporate entity, with enough layers of managment to rival the federal government.)

ETL advertises faster turnaround, and more cooperation with the companies trying to get their product to market.
 
Jim Cavanaugh said:
I find it curious that UL would not list this particular TVSS product (citing safety concerns) but ETL did list it.
Click to expand...

Well if in fact the device does connect N-G, then it does not comply with 1499 period or the NEC. So it is no mystery IMO the UL will not touch it.

N-G mode is easy to protect without a transformer. Simply install a low voltage SAD or MOV between N-G like everyone else does. It is no secret. What this manufacture did was take shortcuts.
 
LarryFine said:
Wait until someone plugs one into a reverse-wired receptacle. :cool:
Click to expand...

The sales people probably call that a "feature" - integral reverse wiring and circuit breaker tester.
 
steve66 said:
The sales people probably call that a "feature" - integral reverse wiring and circuit breaker tester.
Click to expand...
Right. I can see it now:

"Important! If you see and hear a large spark and the lights go off, you might have a wiring issue."
 
Status
Not open for further replies.
Top