surge protectors

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away from a direct lighting strike, what are your experiences with surge protective devices? just installed 2 qo panel surge protectors and they seem like a good idea as opposed to the POCO installed meterbase surge protectors as they charge a monthly fee. then i guess there are surge strips....but how many would you need to protect a modern house?? everything has electronics in it these days, dishwashers, microwaves, washers, dryers, etc...its not just computers anymore. what are your opinions on the different ways of approaching house surge protection?
 

George Stolz

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tundraotto said:
then i guess there are surge strips....but how many would you need to protect a modern house?? everything has electronics in it these days, dishwashers, microwaves, washers, dryers, etc...its not just computers anymore. what are your opinions on the different ways of approaching house surge protection?
Don't discount strip surge protectors - they can save equipment in an open neutral condition, whereas the service TVSS's won't see it. :)
 

bphgravity

Senior Member
Location
Florida
The earlier the surge can be suppressed, the better. This is one benefit of the meter fitted SPD. Plus, if they fail or blow up, they replace it at their cost. Otherwise redundant protection can't hurt. I personally have a surge arrestor at my service, a TVSS at the L&A panelboard and surge outlets for my computer equipment, home entertainment, and guitar equipment.
 

jtester

Senior Member
Location
Las Cruces N.M.
In commercial applications it is common to have different levels of surge protection. The first level often deals with larger amounts of energy and the ones closer to the loads are then left only dealing with a spike that doesn't have much energy.
Also, if a spike is generated internal to the building, a service installation won't eliminate it from affecting the loads.

Jim T
 

tom baker

First Chief Moderator
Staff member
With TVSS:
1. More is better
2. You get what you pay for.
create a xero potential ground at the service with the TVSS and cable/telephone impulse supressors

Use a robost TVSS at the service, and then surge strips for expensive equipment.
Surge strips with coax/telephone ports help to create a equal potential ground.
 

dereckbc

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Plano, TX
Actually the POCO meter base TVSS are one of the best you can get, plus come with a pretty rock solid guarantee. In my area they come with a $50K guarantee of major appliances like HVAC, motors, refrigerators, and exclude point of use electronics. For that they offer Class ?A? point of use devices. What makes the POCO TVSS devices attractive is there is no better place to have one installed, robust in K-Amps per mode, no lead length to connect, and no ground is required, not that ground has a darn thing to do with a surge.

Not all TVSS devices are created equal, far from it. As Tom mentioned you get what you pay for. The next best devices are those with TVSS built into the main panel. Like the meter base units there are no leads involved, so the SPD?s are bolted right onto the bus. The down side is the cost, as it adds hundred$ to a panel for a quality unit. Like the POCO units most of the better ones come with a guarantee.

On the bottom of the food chain are the add-on units to a panel or aka parallel units. These come in all types of flavors and designs from the little cans that screw into a knock-out, to a utility box that mounts next to the panel. Their effectiveness ranges from useless to moderate protection.

Beyond the service entrance you need to have point of use devices installed at each location where sensitive equipment is utilized. These range from term strips to receptacle outlets. Again quality varies wildly from poor to good.

One really needs to understand the ratings, listings, and technologies to identify the dogs from the winners. I can help with that if needed.
 
OK, appreciate the help. I understand that the POCO provided panel mount would offer the best protection, but we want to stay away from any monthly payments. Another important factor was that during power outages the POCO SPD would proveide no surge protection from generator power. These QO panel mount SPD's - (they are like double pole breakers with a lead to Neutral). How do they fare as opposed to the others? are they worth their price and do they in real terms provide protection worth their cost?
 
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bump i guess - derekbc you stated that you might let us in on these MOV varistor QO panel surge protectors. are they worth their cost?
 

petersonra

Senior Member
Location
Northern illinois
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engineer
tom baker said:
The meter base TVSS units are best as they have zero lead length. If you double the lead length you double the impedance.

Double?

2 X 0 still = 0.

There is no way to easily quantify this. Clearly wires are the weak point in a TVSS. Transients tend to have a very fast rise time, and the impedance of the wire is a function of the frequency. The wire itself is not the issue as much as any kinks or coils in it that might add inductance. Even a very small amount of added inductance is a lot of impedance at high frequencies.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
tundraotto said:
so the panel spd's are basically useless? if using surge strips with sensitive equipment?

actually putting the tvss inside the panelboard is probably going to get you the best results. these are fairly robust and fairly pricey, but by most accounts work pretty good.

i am pretty much convinced the plug in strips are of little value other than as a multi-outlet assembly. the reason for this is that most modern electronics have relatively robust power supplies that give the equipment substantial protection. Whatever protection is in the $10 surge strip is far less IMO.
 

dereckbc

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Location
Plano, TX
tundraotto said:
so the panel spd's are basically useless? if using surge strips with sensitive equipment?

Not exactly. What you have to look for is the UL-1449 listing and the SVR (Suppressed Voltage Rating). A good panel mounted TVSS will have a SVR rating of 330 or 400. To have this rating, UL tested the device with a 6-inch lead length. Beyond 6-inches you can add approx 100-volts for every linear inch additional lead length. Here is a decent web site in which I co-authored some years back when the Tranquil line was made by ACT before GE bought them out.

http://www.geindustrial.com/publibrary/pubLibResult.jsp?famId=37&src=treeSearch
 
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