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whole house surge protector with generator

Posted by toomuchtodo (My Page) on
Tue, Sep 26, 06 at 11:03


I am planning on having a generator hooked up to our home soon and am unsure of something.

The generator is a 10kw manual start that will be hooked to the 200 amp main panel via a service rated manual transfer switch. Coming from the main service into the main panel is a Panamax whole house surge suppressor.

Will I still be able to use this supressor? I do have a licensed electrician coming to do the work (he wired the whole house for us), but to be honest he's a little behind the times on some things. I'm just trying to understand this in case he has questions.

Also, somewhat related is we're still experiencing a lot of brown-outs and spikes. We'll be sitting here when all of a sudden the lights get brighter and stay brighter for who knows how long. That and our APC battery back-ups / surge supressors will beep all of a sudden (with or without the lights brightning) Is the Panamax supressor still doing its job, or is it "burned out" from so many spikes?

Thank you for your time and consideration.


Follow-Up Postings:

RE: whole house surge protector with generator


A surge suppressor with a gennie may make sense in some cases although it may cause the both of them to fight each other. I do know with UPS units, they recommend you DO NOT use a surge suppressor downstream ie between the UPS and the load for this reason - however, I always put a surge suppressor between the UPS and the mains supply, my theory being surge suppressors are a lot cheaper than UPS units.

Every little surge you get wears your whole house unit out a little more. I don't know what sort you have or what its clamping speed is, but yes, it's possible yours is worn out (although I don't know what failure mode is, whether it's open circuit - no supply- or supply unregulated)

They do need changing periodically. I suspect your assessment that you need a specialist is correct, you might do better to find someone with more experience on this sort of setup.

If having the suppressor downstream from the gennie is contraindicated, you might be able to introduce the gennie downstream of the suppressor?

RE: whole house surge protector with generator

I'm a little concerned about your voltage variation. A modest amount of this is normal, but drastic changes in voltage should be investigated by the power company.

If your lights brighten when large appliances in your house turn on (air-con, washing machine, etc.) then you should contact the power company IMMEDIATELY. This is a symptom of a loose neutral connection and it can damage or destroy your appliances.

RE: whole house surge protector with generator

Failure mode for surge suppressers is an internal short in the MOVs followed by destruction of the device from overheating.
If it is also overcurrent protected it may not 'clear' and appears as a short with an OCD that will not hold when reset.

RE: whole house surge protector with generator

Hope you don't mind but I'd like to ask about my similar situation.

Our service comes into our main panel in the barn. From there it goes to the service panel in our house (not attached to the barn). And we have a standby propane generator that is not yet hooked up to the service panel in the house (under construction).

Our new home is in an area with frequent lighting strikes (and we have the scorched trees to prove it). We've had the power company out twice in the last 6 months when the transformer tripped. One of the strikes burned out all the exterior lights on the barn and an overload fuse on the well pump in the house. At the time of the strike, the power to house was actually turned off from the main service panel in the barn. Power was just running from the service to the main panel.

I think that getting a whole-house surge protector might help to prevent or at least lessen damage.

Do we need a whole-house surge protector for each ... barn service panel, house service panel, and generator? Or just one surge protector?

I'm sure out electrician will know what to do but I'd like to get an idea of what we will need so I can budget.

RE: whole house surge protector with generator

I'm not an expert, but my sense is that any time you have a run to an outbuilding or a separate subpanel, you want to protect downstream circuits. Nearby (not necessarily direct) lightning strikes can induce huge surges in any run of wiring.

I don't have a meter TVSS. However, I use secondary TVSSes at the house main panel, at the garage subpanel (~150 feet away), and at the barn subpanel (~500 feet away). I do NOT have a secondary TVSS at the house subpanel, which is perhaps 20 feet away from the main, though maybe I should. I also have the usual surge strips at plugin electronic devices.

Yes, they cost something, but I've seen what surges can do. The protection is worth the cost, IMO. This is especially true for your case where there are many nearby lightning strikes.

Hope this helps.

RE: whole house surge protector with generator

My emergency backup generator is a Coleman Powermate with the 11 hp Tecumseh rated for 5500 watts cont/ 6875 surge. Now before you Honda owners jump me for buying a lesser unit, let me say that this is strictly used for power outages in Southern California, so it's usage will average once or twice a year and I don't feel that warrants a more expensive brand.

I realize that the voltage from a portable generator isn't *clean* and am concerned about the electronics in my garage door opener, tankless water heater, and other semi-essential devices that I would like to run off the generator. So what type of surge protector would be suitable to filter the power coming from a generator?

RE: whole house surge protector with generator

You want to run a tankless water heater from a 5.5kW genset? Is this a really small one for just a single lav sink or something? Other than a tiny 3.5kW unit for that purpose, all the electric flash water heaters I've seen use upwards of 12kW. Or is this a gas heater with electric ignition?

RE: whole house surge protector with generator

The water heater is gas so the electrical demand is just for ignition.

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