whole house surge protection

[willlgord]

I just finished wiring my detached garage. ..100 amp sub panel fed from the 200 amp main in the house. Before I can put power on it I have to replace the main panel in which I plan to use a whole house surge protector. This should provide protection for the garage also, shouldn't it?

 

[Dick in Wisconsin]

Tell us more about your whole house surge protection system.

 

[rlitman]

It should, but if you have a separate grounding rod in your detached garage (as you should), it wouldn't hurt to have an SPD in that panel too.

 

[Bigbandguy]

An electrician I know told me just this week that he only mentions whole house surge protectors to people who are close friends or good customers because they tend to reduce the amount of repair work he gets to do for that customer. He said that they are great for the customer but bad for the repair business. I have one on my house and have not lost any devices to near lightning strikes since it was installed... that may be the surge protector or it might be just good luck. I expect the sparkies can shed some better light on this.

 

[Dick in Wisconsin]

I have one on my house and have not lost any devices to near lightning strikes since it was installed... that may be the surge protector or it might be just good luck. I expect the sparkies can shed some better light on this.

Tell us more about it. Make and model, cost, pictures, etc.

 

[willlgord]

This is the device I'm looking at. It plugs into the panel just like a breaker. http://www.amazon.com/gp/aw/d/B008D..._UL100_SR100,100_&refRID=0EBNWJ8JJ9S82EN8QP6Z

 

[rlitman]

Do you have a Square D Homeline main panel? If so, that device would be fine in your main panel, but does not separate neutral from ground, so would not be ok in a subpanel.

 

[Stuff]

Note that if you do put a surge protector at the garage don't use the plug-in type as they are designed for a main panel only that has ground and neutral combined. Those SPDs normally have only one wire - a white neutral. The add-on types that wire up to a double-pole breaker have both green and white.

 

[willlgord]

So it wouldn't protect the sub panel which will be fed off the breaker in the main? Both panels are Square D Homeline.

 

[wyliesdiesels]

So it wouldn't protect the sub panel which will be fed off the breaker in the main? Both panels are Square D Homeline.

It would protect the garage sub if lightning hits the house. If lightning hits the garage then it wont.

 

[willlgord]

I probably won't bother putting one in the garage. ..not many sensitive electronics there. Thanks for the info!

 

[Charles (in GA)]

This plugs into your meter socket, then your meter plugs in on top of it. If your POCO allows it, you can have it done when the meter is out during the upgrade.

http://www.amazon.com/Leviton-50240-MSA-Secondary-Arrestor-Protective/dp/B0019F6X3I/ref=sr_1_9?ie=UTF8&qid=1456431467&sr=8-9&keywords=leviton+surge+protector

Charles

 

[rlitman]

It would protect the garage sub if lightning hits the house. If lightning hits the garage then it wont.

If lightning hits your house OR garage, no SPD is going to do a thing about it.
You can count on major damage.

If lightning hits the aerial wire a few poles away from your house, an SPD may help protect your electronics.

As for how an additional SPD in a subpanel will help, well its a little complicated. But the issue is that no matter how fast or good an SPD is, a fraction of the surge will still get out to every branch off the protected panel. In higher impedance branches, that fraction will be very small. But in lower impedance branches (such as the one that is feeding your 100A subpanel), the fraction might still be significant. The surge will travel up that branch, reflect off the far end of that panel, and return to your main panel. It creates an effect called "ringing". If your subpanel has a good ground source (its own grounding rod would be great), then an SPD there can not only improve your power quality, but can also increase the life of the SPD on your main panel.

 

[rcktpwrd]

This plugs into your meter socket, then your meter plugs in on top of it. If your POCO allows it, you can have it done when the meter is out during the upgrade.

http://www.amazon.com/Leviton-50240-MSA-Secondary-Arrestor-Protective/dp/B0019F6X3I/ref=sr_1_9?ie=UTF8&qid=1456431467&sr=8-9&keywords=leviton+surge+protector

Charles

We have one like this provided by the POCO for a small monthly fee. It is still recommenced to have point of use surge protectors. The one on the meter controls the large surges, like lightening, the point of use ones control the smaller surges from power flickers and whatnot.

 

[westom]

It is still recommenced to have point of use surge protectors. The one on the meter controls the large surges, like lightening, the point of use ones control the smaller surges from power flickers and whatnot.

"Smaller surges" such as power flickers (voltages less than 120 volts) and whatnot are made irrelevant by protection already inside every appliance. Or read its specifications. Concern is for surges that might overwhelm that existing and superior protection - such as a direct lightning strike incoming on AC mains.

That Leviton 'whole house' protector (if properly earthed) does maybe 99.5% of protection. Interior protectors for smaller surges maybe do an additional 0.2%. Yes, those additional protectors are recommended for additional protection. Unfortunately, many forget to include numbers for how much.