surge suppressor ground

[yankj]

does a surge suppressor need to be grounded to operate correctly?

 

[ron]

Typically yes. It shunts transients to ground.

 

[tom baker]

At the service, the SPD operates line to line or line to neutral. The neutral and ground are bonded via the MBJ, so no ground is needed.
Think of it this way, the SPD sends the surge back to the utility.
Theres a little bit more to it, but the answer is no.

 

[dereckbc]

Depends on which mode the transient occurs either in the Differential Mode, or Common Mode.

In the Differential Mode, which around 95 to 98 % of all transients occur, the surge is arrested dissipated between L-L and/or L-N and directed back to the utility.

In the Common Mode the energy appears between L-G and/or N-G and diverted to earth.

But as Tom points out if we are talking about a service entrance N-G are bonded so ground really plays no significant role.

 

[yankj]

I'm speaking here about a surge suppressor that plugs into a 120V receptacle

 

[dereckbc]

I'm speaking here about a surge suppressor that plugs into a 120V receptacle

That is different. In that case a Point of Use device; then L-G and N-G modes are warranted. But I will be honest with you as a user, they can do a much better job than an EC can in this respect.

The best Point of Use devices are the quality term strips with built in TVSS that include power and all I/O devices. Example would be an entertainment center where you have coax, Ethernet, and power. They form a Pseudo single point ground with no lead length all the referenced to a common ground bus inside the term strip. IEEE Emerald Book calls these type of device a surge reference equalizer.

 

[Ohmy]

I've noticed surge strips that do not make use of the ground.

 

[dereckbc]

I've noticed surge strips that do not make use of the ground.

That is why I said a quality term strip.