SURGE PROTECTION

[timmermeier]

In the 2020 NEC you must in stall surge protection when installing a new service . what good does it do if any . what does it protect. and from what ?????????????????

 

[PaulMmn]

Supposed to divert electrical surges coming in on the power lines from The Grid to ground, so the appliances and electronics in your house don't have to do it.
.
Sits in or near your electrical panel.
.
One issue is that a lot of them use MOVs. "MOV stands for Metal Oxide Varistors, a voltage-limiting protection device with nonlinear volt-ampere characteristics." They effectively short an electrical surge to ground.
.
Wikipedia (https://en.wikipedia.org/wiki/Varistor) says, "Varistors can fail for either of two reasons. A catastrophic failure occurs from not successfully limiting a very large surge from an event like a lightning strike, where the energy involved is many orders of magnitude greater than the varistor can handle. Follow-through current resulting from a strike may melt, burn, or even vaporize the varistor. This thermal runaway is due to a lack of conformity in individual grain-boundary junctions, which leads to the failure of dominant current paths under thermal stress when the energy in a transient pulse (normally measured in joules) is too high (i.e. significantly exceeds the manufacture's "Absolute Maximum Ratings"). The probability of catastrophic failure can be reduced by increasing the rating, or using specially selected MOVs in parallel.[12]
Cumulative degradation occurs as more surges happen."
.
In other words, they wear out, and need to be replaced.
.
They sacrifice themselves that your hi-fi and wide-screen TV will live.
.
For point-of-use surge protection, I like the Zero Surge brand (https://zerosurge.com/). They do NOT use MOVs in their surge protectors. I have 4 of their units in my house-- computers, hi-fi, wide-screen TV, etc. I can only provide negative feedback-- I haven't lost anything, and get at least a couple good thunderboomers a season.

 

[Speedskater]

a] Most of the power line surges have little interest in going to ground or Planet Earth.
They want to get back to their source, which is that big power company transformer down the street.

b] Metal Oxide Varistors
MOV's have been around for a half century, as have many of those horror stories. MOV's have come a long way.

c] Zero Surge protectors, are very pricey but great point-of-use protectors. But are not available as whole home units.

 

[tom baker]

In the 2020 NEC you must in stall surge protection when installing a new service . what good does it do if any . what does it protect. and from what ?????????????????

They work well.
“More is better and you get what you pay for”, Mike Holt.
IE a quality SPD at the service and then point out use at electronics
Where I worked I had a lot of failures on electronic power supplies, started installing Leviton SPDs, one on 480 and one on 120/240. No more failures.
I had a SPD get taken out by a car pole accident overvoltage with no electronics damage.
The SPDS I used had MOVS and gas tubes, with alarm.
Anyway something is better than nothing.

 

[gadfly56]

Supposed to divert electrical surges coming in on the power lines from The Grid to ground, so the appliances and electronics in your house don't have to do it.
.
Sits in or near your electrical panel.
.
One issue is that a lot of them use MOVs. "MOV stands for Metal Oxide Varistors, a voltage-limiting protection device with nonlinear volt-ampere characteristics." They effectively short an electrical surge to ground.
.
Wikipedia (https://en.wikipedia.org/wiki/Varistor) says, "Varistors can fail for either of two reasons. A catastrophic failure occurs from not successfully limiting a very large surge from an event like a lightning strike, where the energy involved is many orders of magnitude greater than the varistor can handle. Follow-through current resulting from a strike may melt, burn, or even vaporize the varistor. This thermal runaway is due to a lack of conformity in individual grain-boundary junctions, which leads to the failure of dominant current paths under thermal stress when the energy in a transient pulse (normally measured in joules) is too high (i.e. significantly exceeds the manufacture's "Absolute Maximum Ratings"). The probability of catastrophic failure can be reduced by increasing the rating, or using specially selected MOVs in parallel.[12]
Cumulative degradation occurs as more surges happen."
.
In other words, they wear out, and need to be replaced.
.
They sacrifice themselves that your hi-fi and wide-screen TV will live.
.
For point-of-use surge protection, I like the Zero Surge brand (https://zerosurge.com/). They do NOT use MOVs in their surge protectors. I have 4 of their units in my house-- computers, hi-fi, wide-screen TV, etc. I can only provide negative feedback-- I haven't lost anything, and get at least a couple good thunderboomers a season.

Several decades ago, I did lighting design at a community theater. The individual circuit outputs in the power supplies had VAR's in them. One night we had a cascade failure in one of the 6-circuit power supplies. It sounded like a machine gun going off in the lighting booth.

 

[David Castor]

It will help you pass inspection. Properly installed, they can provide a good degree of protection against voltage transients due to lightning or switching transient.

 

[Seven-Delta-FortyOne]

They protect against voltage surges, most effectively from the power line, and with some lesser degree of effectiveness, in general, from lightning strikes.

We have several at the ranch, for all the houses. We lose power dozens of times a year, and many times it catastrophic.

Best one was 5 years ago or so when a 150’ tall Douglas fir fell across the 12kV lines that feed out hill. Heard a loud boom in the middle of the night. It was a big storm too.

In the morning, the SPDs at the main panel were blown, and the SPDs at the sub panels had blown off the buss bar, blew the panel covers open, and left a black char mark on the door.

The POU SPDs we all tripped. I replaced all the SPDs, and everything worked except the tv, which didn’t have the POU one also.

PG&E paid to replace all the SPDs and the TV.

Earlier this year I replaced the ones in the service panels again. Both were blown at some point. Nothing in any of the houses were damaged.

 

[tom baker]

About 20 years ago a homeowner contacted me as he had found an article on SPDs I written for a national traffic signal magazine. In his neighborhood, a high voltage line, 112 kva dropped onto a 12.5 kva line.TVs and microwaves were toast.
I recommended Liebert SPDs, which were purchased and installed
Later the same thing happened, hv onto lv line
But there was no damage in the homes with SPDs. Both cases were due to broken insulator

 

[tom baker]

Supposed to divert electrical surges coming in on the power lines from The Grid to ground, so the appliances and electronics in your house don't have to do it.
.
Sits in or near your electrical panel.
.
One issue is that a lot of them use MOVs. "MOV stands for Metal Oxide Varistors, a voltage-limiting protection device with nonlinear volt-ampere characteristics." They effectively short an electrical surge to ground.
.
Wikipedia (https://en.wikipedia.org/wiki/Varistor) says, "Varistors can fail for either of two reasons. A catastrophic failure occurs from not successfully limiting a very large surge from an event like a lightning strike, where the energy involved is many orders of magnitude greater than the varistor can handle. Follow-through current resulting from a strike may melt, burn, or even vaporize the varistor. This thermal runaway is due to a lack of conformity in individual grain-boundary junctions, which leads to the failure of dominant current paths under thermal stress when the energy in a transient pulse (normally measured in joules) is too high (i.e. significantly exceeds the manufacture's "Absolute Maximum Ratings"). The probability of catastrophic failure can be reduced by increasing the rating, or using specially selected MOVs in parallel.[12]
Cumulative degradation occurs as more surges happen."
.
In other words, they wear out, and need to be replaced.
.

SPDs divert surges back to the other line or to neutral. Very little goes to earth due to the MBJ
And repetitive surges damage electronics and the SPDs do yes they wear out. Typical SPDs have an end of life indication

 

[Barbqranch]

Does it make any difference where a SPD is located on a panel?

 

[electrofelon]

In the 2020 NEC you must in stall surge protection when installing a new service . what good does it do if any . what does it protect. and from what ?????????????????

Note this is only for dwelling unit services.

 

[Speedskater]

Does it make any difference where a SPD is located on a panel?

As near the power input connections as practicable.

 

[sgtsparky]

Does it make any difference where a SPD is located on a panel?

Yes it makes a difference the SPD should be located close as possible to your main, this reduces line transients the next thing to think of is at point of use where you have motor loads that can generate counter EMF spikes, I have one at my large air compressors prior to putting them in I had several radios and a microwave die, that was 20 years ago, when I moved to the mountains about 10 years ago I also added UPS protection for my big screens / equipment. These are the highest level of protection and the batteries have to be changed every 3-4 years, both are worth the investment in my opinion.

 

[AC\DC]

Is this not another design issue not a safety issue. Unless the premise is it will protect your smokes from failing.

 

[electrofelon]

Is this not another design issue not a safety issue. Unless the premise is it will protect your smokes from failing.

gotta protect those AFCI breakers We know how important those are