Surge Breaker in a Sub Panel

[Mr onetwo]

I have been trying to clarify this question in my mind....in a sub panel where the neutral and ground are not bonded, is a surge protector device like a Homeline HOM2175SB completely ineffective and unnecessary?This is stated in several other threads...I will try to find one. I have a 200 amp meter panel with 2 100 amp breakers feeding my house and detached garage separately.Is there any means of surge protection that makes sense in this situation? https://www.homedepot.com/p/Square-...r-Surge-Protective-Device-HOM2175SB/100182531

​

 

[PCustoms]

....in a sub panel where the neutral and ground are not bonded, a surge protector device like a Homeline HOM2175SB is completely ineffective and unnecessary.

What causes it to be ineffective?

 

[mike93lx]

What causes it to be ineffective?

I have the same question.

Unless surges only come over the ground, I'm not seeing the problem

If it was ineffective, I'd expect an exclusion in their warranty in that application and it to be called out in the installation instructions. Neither are the case

 

[Mr onetwo]

I worded the thread wrong guys...it should have been a question...sorry it is corrected

 

[Mr onetwo]

https://www.garagejournal.com/forum/threads/whole-house-surge-protector.496418/ read post #18 makes sense

 

[Mr onetwo]

"Protector in a sub-panel is ineffective. A subpanel typically does not have a direct (ie less than 10 foot) connection to earth ground electrodes. Since earth ground does all protection, then that protector is made ineffective. And it must be single point earth ground. Same earth ground that connects to a main breaker box."

 

[mike93lx]

https://www.garagejournal.com/forum/threads/whole-house-surge-protector.496418/ read post #18 makes sense

Surge protector threads always attract a lot both sides.

Personally, they are cheap enough to be worth it for me. I got a good deal on the homeline units you linked, so I have four between my two main panels, plus I added one in my pool subpanel. If they even protect one piece of equipment (pool pump, heat pump, one a/c, a fridge, etc), they've paid for themselves. If they do nothing, c'est la vie, I just sleep better.

 

[mike93lx]

"Protector in a sub-panel is ineffective. A subpanel typically does not have a direct (ie less than 10 foot) connection to earth ground electrodes. Since earth ground does all protection, then that protector is made ineffective. And it must be single point earth ground. Same earth ground that connects to a main breaker box."

So just add a ground rod if that is the concern

 

[Mr onetwo]

is there a protector that could go out by the meter? Sub panel is in middle of the house.

 

[mike93lx]

Do you have breakers at the meter pan? Any open slots?

Most surge units connect to the side of the panel and wire into a two pole breaker. Although I don't know if they are rated to be exposed to the weather.

 

[wyliesdiesels]

https://www.garagejournal.com/forum/threads/whole-house-surge-protector.496418/ read post #18 makes sense

that guy is something else and frequently posts BS... he only comes on this forum when a surge thread is posted... then he crawls back to wherever he came from

 

[Mr onetwo]

What you guys makes sense...I have room at the top to put the one in that I have, so I will.

 

[Metal-Marc]

I plan to install one in my garage.

 

[Innovate1]

That unit (HOM2175SB) only has three terminals so I used it in my main panel but in my garage subpanel used a unit that has separate ground and neutral connections.
https://www.homedepot.com/p/Square-D-50-kA-Home-Electronics-Protective-Device-HEPD-HEPD50/300716359

 

[rlitman]

... read post #18 makes sense

Westom posts a lot on the subject. Much of it is even correct. Much is also misleading.

He makes the valid point that the lower the impedance between an SPD and ground, the more surge energy it can divert. But he also falls into the trap of assuming that surge currents are nearly unlimited (like a direct lightning strike). However, barring such a direct strike, surge currents are not limitless by any means. In fact, surge currents are dependent on impedance to the source. Because of this, the SPD in your subpanel will protect devices in that panel as well as the SPD in your main panel. And it will even provide a degree of ring wave protection to devices in your main.

So, yes, the service entrance is by far the best place to position a single SPD, but there's no harm in having them placed in panels and even in equipment ALSO. The benefits may be smaller, but they do still exist. And in some situations, they may even be critically important.