surge protector

Is it appropriate to has a surge protector tapped into the main service lug?
I have had a couple of people tell me this is ok, but want to get a definitive answer.

Unless the lug is rated for multiple conductors, its wrong.

Thank you! I keep saying that.
What would be the correct way to install a surge protector?

across a two pole breaker.

Double taps are wrong yes a proper way is to install a Breaker . see post #3

Here’s what the NEC has to say about that:

That terminal is definitely not listed for two conductors.

I did a brief search, but I can’t figure out how those protectors work… they always seemed like snake oil to me.

How can a device, plugged in parallel to the protected load, and not in series, protect that load?

They use a combination of MOVs and capacitors to deal with spikes and noise on the power line.

They are not snake oil but their effectiveness can vary greatly.

Thanks Mike.
I get asked about surge protection by clients, and I usually steer them toward the “meter sandwich” surge protection offered by the local PoCo…
At least they cover any damage up to 10,000 if it doesn’t work.

Well worth the $4.95 a month that they charge for it.

Hello All,

Other than a clear violation of 110.3(B) and 110.14(A) as noted. What you have also done now is place a small conductor (as represented by the SPD Lead) onto a conductor that is I will assume a Service Entrance Conductor and now it is unprotected from overcurrent.

Now, not knowing if this is a Type 1 SPD which is to be installed between the source transformer and the line side of the service disconnect or if this is a Type 2 SPD that is to be installed (by NEC and Manufacturer) and protected by an overcurrent protective device.

So in conclusion you have many things to think about when looking at this versus just the terminal being a violation. You have some other serious safety concerns to elaborate on.