What Type Of Surge Protection House Circuit Breaker ?

[G Henslee]

[Robert11]

Hello:

Will probably be replacing a standard house circuit breaker with a surge protector circuit breaker to provide protection for a furnace board that seems to be pretty succeptible to lightning strikes (please see my previous post).

The furnace runs off a dedicated 15 amp line, protected by its own breaker in the main house panel.

Apparently they come in two flavors.

One being the standard "surge protector," and the other type a "transient voltage surge protector".

They both seem to be available incorporated into 15 amp circuit breakers that fit in the main house panel box.

Which do I probably want ?

Why ? What are the differences re protection, etc. ?

Thanks, Bob

[Pop]

....

If you've got a link or anything to show those items, it might be possible to make some judgements. Any surge protector is a "transient voltage" surge suppressor, so why they'd have two different names within one product line is interesting.

The two most important specs you want are the number of joules of energy it can withstand, and the length of time it can withstand that much power. There are other relevant specs of course, but to get too far into them here isn't relevant, IMO, without knowing more about the items.

I'm offering to check them out because I've been considering the same sort of thing too, but haven't gotten too serious about it yet.

HTH, Pop

[Robert11]

Hi,

Take a look at pg 9 in the Attachment.

Please let me know what you think.

They certainly appear to be two distinct types.

Bob

begin 666 surge_2.pdf (application-pdf Object).URL M6TEN=&5R;F5T4VAO

[PipeDown]

I think they are the same thing but if there is a difference, I would expect the transient one to react faster but not significantly different. To compare, you want to look at the amount of energy they will absorb in the event of a surge. This is usually in units of Joules if it is even listed. It will protect you from a modist surge from a distant strike but probably will fry if you get a direct strike. It's sacrifice may save something else down the line though.

I got one that is the size of a double breaker and the model number was listed on the inside sticker of the panel's door. I got it just for CYA purposes cause we don't get much lightning here in SF bay area but surges can happen when equipment fails during wind storms or car accidents with utility poles. Hard to say if it ever did anything.

From an engineering POV, Transients are short duration events while surges can last quite a bit longer but as long as they are temporary, can be called transient as well.

[Pop]

I'm sorry, much as I'd like to help, I don't open attachments. Perhaps someone else will take a look for you, but I cannot make exceptions.

Perhaps someone could put them on a web site for you and then just post the URL here?

Apoligies

Pop

[w_tom]

First, it does now matter whether that circuit breaker protector is on a furnace circuit or installed as a 20 amp breaker for another circuit (on the same phase). Either provides the same transient protection to that furnace. Or as that Siemens app note says, "An electrical surge, whether it is caused by electrical equipment or lightning, always seeks ground. Any component between the source of the surge and ground can be damaged."

IOW the protector inside that Siemens circuit breaker connects as if just another light bulb - connects in parallel

- is not electrically located between a lightning cloud and the furnace. The protector does not stop or block surges. It shunts.

Second, protector is not the open contacts of a circuit breaker. That would be (futilely) stopping or blocking transients. A 'whole house' protector inside that breaker protects by 'shunting' a surge to earth ground. IOW the internal protector operates independently of the circuit breaker.

They are called shunt mode protectors. This Siemens breaker installed on any circuit (of same phase) protects the furnace. Protector inside that circuit breaker shunts the transient to earth ground - whether it is a 15 amp furnace circuit breaker or any other (same phase) 20 amp breaker.

The Siemens breaker (like all shunt mode protectors) does not stop, block, or absorb surges. It shunts. It must have a single point earth ground to shunt to. That means earthing may need be upgraded to meet or exceed post 1990 NEC requirements.

Third, the effectiveness of a protector during one transient is determined by quality of that earth ground.

Effectiveness of a protector over many transients is determined by its joules rating. A protector shunts - just like a wire. More joules means 'the wire' is thicker. Any protector that fails during a first transient was woefully undersized - totally ineffective - too few joules - just like so many plug-in protectors. An effective protector shunts direct lightning strikes to earth and remains functional. Joules and amps numbers determine protector's life expectancy. Install two such Siemens breakers in the circuit box (to double the number of joules); life expectancy of both breakers increases exponentially.

For residential 'whole house' protectors, minimally sufficient is 1000 joules and 50,000 amps. Does not matter whether it is a "surge protector" or a "transient voltage surge protector". Joules determine protector's life expectancy. Earth ground determines its single transient effectiveness.

Fourth, the Siemens solution has one difference over other 'whole house' protectors. Once a protector has failed, then that circuit cannot be reset; circuit breaker must be replaced. The circuit breaker trips long after a transient has come and gone. For example, 300 consecutive transients could come and go before the circuit breaker trips. The circuit breaker is not protection. But once the internal protector has failed, then a Siemens breaker will no long provide power to the furnace.

Fifth, there is no 'functional' difference between TVSS and surge protectors. Both are only as effective as their earth ground, as the Siemens app note even suggests. Most critical is the quality of that single point ground AND how wire to that earth ground is routed. For example, sharp wire bends mean a compromised protector. Ground wire bundled with other wires may induce transients on those other wires. And so to summarize it: a protector is only as effective as its earth ground.

Earth ground determ> Will probably be replacing a standard house circuit breaker with a

[Pop]

"Chris Lewis" wrote in message news: [e-mail]...

Errr, that's sort of a generalization and not really very descriptive? A transient voltage is a passing, not permanent, voltage. In general, a surge is an increase in the supplied voltage, yes, and may last for several cycles or more. A transient voltage is really one which appears and then is gone, its duration generally being "short", but that's not very descriptive either. It's "short" when compared to a sixteenth of a second though, and then it becomes more descriptive.

LIghtning originates transients, which may actually be in the initial order of seconds of current flow. A lightning strike is not a mS or a uS event; it's actually many hundreds of transients all at once, which can in turn have the effect of causing a "surge" after it's gone against all the capacitive power factor equipment on the lines and the inductive properties of many transformers. Add to that the many expanding and collapsing electrical fields along miles of wire and you have a surge.

I used to use mains recorders and got to examine a lot of lighting strikes in South Dakota where the power lines aren't all that good and none of them were underground. I recall one strike which created a 168 cycle long surge at the outlets; of over 400 volts peak on a 330V reference, in one direction, and another set of 4 second ringing that peaked at 3xx volts for about three more seconds. THAT was a surge! You'll find, actually, that most "transient" voltages, spikes or whatever you'd like to call them, are generated from within the premises of a building where they are a problem. It's interesting stuff.

Dunno why we're discussing this; memories, I guess.

Pop

[Chris Lewis]

According to Pop :

Surges are long duration events, with not that high of a voltage. Transients are very fast very high voltage events. While some protectors will do both, it's not necessarily so.

Lightning generates transients. Usually not surges.

[Bud]

I generally agree with the post, it gives a good description.. The TVSS is warranted only for the circuits connected downstream from it (connected to the 2 circuit breakers). The TVSS; (and SURGE protector) are connected to both phases. They would protect L1-L2, L1-GND, L2-GND.

The TVSS is connected on the load side of its breaker. The current it causes may cause the breaker to trip.

The protector will shunt to ground. This could cause the ground voltage to rise over the 'real' ground potential. The furnace would see the hot-neutral-ground voltage and would not know that the potentials suddenly rose over the 'real' ground potential. Unless there is another ground reference, like a telephone line, I don't think a ground is as important as indicated, though one certainly wants a good ground.

A strike on a lightning rod (now called air terminals?) will raise the potential of the local ground above 'real' ground. The lightning rod ground must be bonded to power and other building grounds. The potential of the whole house will temporarily float up.

The joule rating is the energy the device can pass in one event. If I remember right, MOVs are progressively damaged when they shunt high energy/high amps. The joule rating is generally related to the life. Actually the surge current rating probably indicates a 'thicker wire' and the joule rating would be the heat dissipation rating of the wire - so the wire doesn't melt.

As I read the note, the TVSS/breaker may trip when a surge hits and have to be reset. If the device fails, the pilot lights go out but the circuit breaker probably will still set.

The SURGE supressor, according to the note, meets the same standard as the TVSS plus an additional one. It can be connected ahead of the service disconnect (but I don't know how this connection is made). If connected downstream from a 20A breaker, the alternate method shown, it is similar to the TVSS.

I presume both could cause the breaker to trip on a long event - in the

1 cycle range (if the SURGE protector is connected downstream from a breaker). The TVSS would still protect the 2 circuits it is connected to, the Surge protector wouldn't protect anything after the trip.

The TVSS has a $20K warranty for the 2 circuits downstream. The SURGE protector has a $10K warranty but limited to 3 years, and the device must be installed by a "qualified" electrician. The SURGE protector has a significantly higher Joule and surge current rating.

When installing these devices it is important the keep wires short. For best system protection install the device breaker in the nearest position to the service breaker.

Bud--