Surge protector connections

[goldstar]

In a recent post I noticed the leads of a whole house surge protector landed on the service lugs ahead of the main along with the SEU wires. I believe, at one time in the minds of many electricians, this was a generally accepted practice. However, I don't believe this was ever allowed by the NEC. I'm sure the thinking was that if there was a power surge the installer wanted to make sure the surge protector worked without the possibility of interruption by a breaker.

That being said, most manufacturers today suggest that you land those wires on a 2-P breaker and as close to the main breaker as possible. It is my understanding that if a power surge occurs the over-voltage will spill off to ground via the MOV's within the unit. If I am wrong on this would someone please correct me ? Also, if there is an extreme power surge condition or a close lightening strike wouldn't the breaker trip leaving the panel unprotected thereafter ? I'm guessing if you get a direct lightening hit you can kiss it good bye.

 

[DanS26]

In a recent post I noticed the leads of a whole house surge protector landed on the service lugs ahead of the main along with the SEU wires. I believe, at one time in the minds of many electricians, this was a generally accepted practice. However, I don't believe this was ever allowed by the NEC. I'm sure the thinking was that if there was a power surge the installer wanted to make sure the surge protector worked without the possibility of interruption by a breaker.

That being said, most manufacturers today suggest that you land those wires on a 2-P breaker and as close to the main breaker as possible. It is my understanding that if a power surge occurs the over-voltage will spill off to ground via the MOV's within the unit. If I am wrong on this would someone please correct me ? Also, if there is an extreme power surge condition or a close lightening strike wouldn't the breaker trip leaving the panel unprotected thereafter ? I'm guessing if you get a direct lightening hit you can kiss it good bye.

Here is one company still recommending to install in the main service lug. Not sure if most panel manufacturers would allow double lugging in their equipment. If you look on page two they recommend to use their special flat blade terminals which are supplied.

http://www.pspproducts.net/T1B160-TGEN160 Installation InstructionsUpdated092014.pdf

Maybe the flat blade terminal is OK but it seems to me that adding that terminal would change the torque specs on those lugs especially in conjunction with aluminum wires. I personally would not recommend it.

 

[junkhound]

would not recommend it re spade lugs

+1, spade lugs a very bad idea for main surge protectors.

Have done a lot of testing of arrestors (mostly for military base use) and have seen multiple cases where the magnetic forces generated by lightning currents pull the spade lugs off the terminal unless the spade terminals are spot welded .

PS: for extreme direct lightning, have even seen magnetic forces due to lightning current BREAK (not fuse) 250 MCM that was not clamped down ever 4 " or so.

 

[GoldDigger]

In a recent post I noticed the leads of a whole house surge protector landed on the service lugs ahead of the main along with the SEU wires. I believe, at one time in the minds of many electricians, this was a generally accepted practice. However, I don't believe this was ever allowed by the NEC. I'm sure the thinking was that if there was a power surge the installer wanted to make sure the surge protector worked without the possibility of interruption by a breaker.

That being said, most manufacturers today suggest that you land those wires on a 2-P breaker and as close to the main breaker as possible. It is my understanding that if a power surge occurs the over-voltage will spill off to ground via the MOV's within the unit. If I am wrong on this would someone please correct me ? Also, if there is an extreme power surge condition or a close lightening strike wouldn't the breaker trip leaving the panel unprotected thereafter ? I'm guessing if you get a direct lightening hit you can kiss it good bye.

There are three types/classes of surge protector listed by UL for mounting is a load center.
One type requires a branch breaker of a specified size, a second type can be connected to the panel bus, protected only by the main, and the third can be connected directly to the service wires.
Guess which is most expensive.

 

[goldstar]

There are three types/classes of surge protector listed by UL for mounting is a load center.
One type requires a branch breaker of a specified size, a second type can be connected to the panel bus, protected only by the main, and the third can be connected directly to the service wires.
Guess which is most expensive.

How do you wire directly to the service wires without violating the listing of the lugs ? Are they rated for that type of connection ? The wires connected to the surge protector are a lot smaller than the service conductors and can melt in an extreme condition I would imagine.