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  1. #1
    Join Date
    Dec 2008
    Posts
    18

    Default Whole House Surge protector

    Hi,

    I'm looking to install a whole house surge protector in my 150 amp panel. I remember an electrician telling me that the panel is at max capacity despite there being a few open slots.

    Slots 2 and 4 (hopefully "slots" is the right term for it) are currently open, which I believe would be the right location to install the whole house surge protector. My question is, can I even add the surge protector if the panel is already maxed out? I have no idea how this all works.

    Any advice will be greatly appreciated!

    Thanks!

    Dave

  2. #2
    Join Date
    Aug 2007
    Location
    The Great White North
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    Default Re: Whole House Surge protector

    The surge protectors don't draw any load ( very very little only to power up the LED status lights ) . The only thing adding the surge protection would contribute is filling the two remaining slots ( or spaces ) -- perhaps this what you mean by maxed out ?
    "" an ounce of perception -- a pound of obscure "
    - Rush

  3. #3
    Join Date
    Jun 2007
    Location
    Fayette County, Ohio
    Posts
    5,558

    Default Re: Whole House Surge protector

    I have no idea what he means by max capacity unless he did a load test. Unless your house is extremely large and/or you have electric heat, I doubt you would ever come close to using a full 150 amps. As Canuk says the surge suppressor uses little power so should not add to load.

    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

  4. #4
    Join Date
    Jan 2011
    Location
    Columbiana, Alabama
    Posts
    623

    Default Re: Whole House Surge protector

    Dmurr, you can buy surge protectors that: mount inside the service entrance panel on a stab, lay inside with wires run to an existing two pole breaker & the neutral, outside the panel through a knock-out (run wires to a 2 pole breaker and the neutral bus, per directions.

    Keep the wires as short and straight as possible (3" to 4" is good), or the lightning will jump off the wire and you will loose your protection.

    It's a good investment that can save a bundle. You may never know what didn't burn your house down, unless the protector melts during a storm.

    Good Luck from Columbiana, Alabama
    Maurice Turgeon, http://thesemi-retiredelectrician.com

  5. #5
    Join Date
    Dec 2008
    Posts
    18

    Default Re: Whole House Surge protector

    Guys,

    Thanks a lot for the advice. I really appreciate it. I have a 2,000 sq. foot house that runs on oil heat (punishment for living in Rhode Island), so I'm definitely not using a ton of electricity.

    And I'm not sure what my electrician meant either, but I thought I'd pass it along.

    Thanks again!

    Dave

  6. #6
    Join Date
    Jan 2010
    Location
    Northern Virginia
    Posts
    975

    Default Re: Whole House Surge protector

    Do these "whole House" surge protectors prevent damage from surges within the house (like from a loose neutral in a j-box) or just on the incoming service? Both?
    Casey
    Remove not the ancient landmark, which your fathers have set.

  7. #7
    Join Date
    Aug 2007
    Location
    The Great White North
    Posts
    4,045

    Default Re: Whole House Surge protector

    The protectors mounted in the panel only handle incoming surges on the service lines. Surges created within the home are handled by point of use protectors --- the kind you plug in --- which should also be used even though you may have a whole house protector.
    "" an ounce of perception -- a pound of obscure "
    - Rush

  8. #8
    Join Date
    Jan 2011
    Location
    Columbiana, Alabama
    Posts
    623

    Default Re: Whole House Surge protector

    Most surge suppressors have at least three Metal Oxide Varistors (MOV) rated 130V for use on a 120V circuit. They're about 3/16" thick and 1 1/4" in diameter. They have two leads and connect: one line to line (across black and white). Another goes from hot to ground and the third goes from neutral to ground.

    For more protection five or more may be tied across each point mentioned above. Years ago when they first came out I ordered one to protect an entire industrial facility (which it did). The box was riveted together and a warning label stated if the box was opened it voided the warranty (which I did). The 480V/277V device contained hundreds of MOV's.

    Whole house units use a 260V MOV across the two hots, usually just tied across a 240V 2 polebreaker. The hot-ground and neutral are 130V.

    They can stand very high peak voltage spikes lasting fractions of a second long. In the case of an open neutral where 200V or more may be felt across a TV for long periods of time both the TV and the 130V MOV are usually fried to a crisp.

    Good Luck from Columbiana, Alabama
    Maurice Turgeon, http://thesemiretiredelectrician.com

  9. #9
    Join Date
    May 2008
    Location
    Pacific Northwet
    Posts
    1,361

    Default Re: Whole House Surge protector

    All MOV surge supressors have a "joule rating." A power surge is also measured in joules. MOVs get used up. So if you have a 5,000 joule MOV, and you get a 20 joule surge, the MOV is now good for 4,980 joules. (That's a BIG surge suppressor. Most are rated 500-1500 joules, and that rating is the sum of all the MOVs in the supressor. So if you've got a 1200 joule supressor, that's probably 400 joules hot-neutral, 400 joules hot-ground, and 400 joule neutral-ground. The 400 joule neutral-ground is unlikely to ever come into play, so your effective rating is more like 800 joules.)

    As you can see, eventually it will wear out and will no longer be able to protect your appliances. That's why it's a good idea to replace the surge protectors for your electronics every several years (more often if you have dirty power or a lot of electrical storms).

    Some have LEDs that indicate protection is working. They do not tell you when it is *almost* used up. So if there's only 100 joules left and you get a 200 joule surge your appliances and electronics are toast. (That's a BIG surge you'd only see in a direct lightning strike or a primary utility line contacting your residential feeder.)

    That said, there are SOME surge protectors that will interrupt the circuit when they fail. I'm not aware of any whole-house protectors that provide this kind of protection.
    Last edited by Fencepost; 10-27-2011 at 01:21 AM.
    The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.

  10. #10
    Join Date
    Jan 2011
    Location
    Columbiana, Alabama
    Posts
    623

    Default Re: Whole House Surge protector

    Good advice Fencepost and would like your opinion:

    I read somewhere that typical housewiring will tend to limit spikes to about 600V due to clearances in devices etc.

    Also, I feel secondary surge strips located around a house will add further protection to not only the appliances plugged into them but the whole house. By their very nature their MOV's are connected L-L, L-N & L-G so wouldn't "more be better"?


    Good Luck from Columbiana, Alabama
    Maurice Turgeon, [URL="http://thesemi-retiredelectrician.com"]

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