Electrical Power Surge Damage
I recently had a power surge that knocked out half my appliances. The electrical provider identified the problem (lack of neutral caused by corroded insullation on the underground lines running from the transformer at the street to our house) and they dug up repaired the line in three places. They have also indicated that they will pay for damaged appliances. It will run into the thousands of dollars. We were all lucky that the house did not catch on fire! My concern is three-fold:
1. What is the “proper” level of compensation for such appliances. Should this be determined by the replacement value or should the items be depreciated according to age? Who determines what is fair? How is latent damage addressed? When an applaince is new and still covered under warranty and reparied at no cost, what is the future indemnification of the utility should this appliance fail within the next 2-3 years (once it is “out of warranty)? My homeowners insurance is going to take a position that any future electrical defects are tied to this intance.
2. How can I determine the integrity of the wiring of my home? The smell of burnt wiring permeated our home — even in areas where there was no evident damage to appliances. How will I know that I wont’ have future problems with outlets/switches? Could there be a fire hazard from damage to the sheathing on in-wall wiring? I have contacted several electrical contractors and they indicate that they don’t know of any way to check in-wall wiring for possible latent damage.
3. Are there particular problems that I should be on the watch for . . . anticipating?
4. Why weren’t the power lines installed in conduit The house was built in 1974? (The utility says they now do so with new construction.) Is this not required by International Electrical or Building Codes? How do I find out? If this is a new requirement, how can I determine when it became effective?
5. The corrosion on the wiring at the three points where the line was defective (at approximately 3-4 feet deep) was visibly evident, looked similar to a car battery covered with white powder. They simply repaired the line at those three points and covered it up. Logic states that the line in corrided throughout it’s 90″ run. To avoid any future liability, why didn’t they simply place the line in conduit?
Replies
#2 Rent a keyhole cam or contact an electrician with one and drill some small holes and check the wiring out in several placeswhere there isn't insulation...in particular in the worst locations for damaged appliances. I would hire an electrician that can do this and bill their charges back. In my admittedly simple mind, it would seem like the damage would start at the panel and go from there but I really don't know.
#1 I would hold out for complete replacement value. Its what your normal insurance policy would cover.....speaking of which, why are you talking to the electric utility at all? Your homeowners should cover this and your insurance company should be settling up with the utility. Thats why you give your insurance company the right of subrogation so they can stand in your shoes and sue those who have harmed you.
#5 your logic seems correct but I don't know how you argue with them. Seems like they would want to replace the entire line but what do I know. This is a situation where you insurance company may be of assistance. They may argue on your behalf that the line be completely replaced. It may also be that they made temporary repairs and put you on a wait list for complete replacement. You could always retain an attorney and claim emotional distress from worrying about the unreplaced line. that should get their attention.
Using conduit for your service entrance would be very unusual, at least in our area.
To look for damaged wiring the best thing to do is to open up outlets and look at the exposed insulation. In general (which is to say there are exceptions) wire will get its hottest near the connections, so the exposed insulation is something of a "canary in a coal mine".
With this sort of event a good electrician should be able to figure out which circuits were apt to be overloaded, rather than needing to check out every circuit. (And, in fact, it's unlikely that any of your circuits were actually overloaded. There may have been damage to outlets where plugs overheated, but that doesn't translate into an overloaded circuit.)
You should make (while it's as fresh in your mind as possible) a list of what was plugged in where when this happened, what lights were turned on, etc, for reference by the electrician.
Basically, half the circuits in your house experienced over-voltage and half under-voltage. Under-voltage can damage electric motors, but usually nothing else, so the (non-motor) devices plugged into the under-voltage circuits are probably OK. Over-voltage can damage just about anything.
Wizzing contest
Poco is going to settle with you for appliance and electrical equipment damages done. Once you sign the check, they are done with additional claims agianst that particular incident.
That is the way they will and the courts will deal with it. If you want future damages covered you need a really good attorney and be willing to spend some big $$ up front. You won't get a dime untill that suit is setteled (read that as years if the dollar amount goes over the small claims limit in your state).
Keep searching for an electrical contractor to check the wiring in your house. Look for a contractor that does commercial and industrial work. Ask them to megar your house wiring. Talk to your HO insurance company about them helping or paying for this type work. It isn't cheap or easy. Industrial electrician rates run upwards of $75/hr. and it is a time consuming job.
Your house was built in 74 and underground SE was legal in that version of the NEC. The house is therefor "grandfathered" under that code. My concern at this point would be more about the splices they put in. I'm not a big fan of underground splices unless they are in vaults where they can be checked. They are legal, but my preferance would have been to replace the whole SE cable, maybe even pay the ugrade to conduite.
Me, I take the settlement for obviouse damage. Then I salt away a little for future repairs that may or may not be associated with the surge damage a few years from now.
True, lights that flicker much more than seems proper, and, in particular, lights that get BRIGHTER when they flicker is strong signal of an open neutral problem. Paying attention to the warning signs can prevent major problems down the road,
(Makes me wonder why I've never heard of an "open neutral sentry" device that would warn of this problem.)
Standard outlet tester
cover this, does'nt it?
Nope.
> Standard outlet tester cover this, does'nt it?
No. Why would it? You should know what that outlet tester reports. For example, it can report a defective safety ground. But it cannot report a good safety ground. It cannot report earth ground. It cannot report low voltage created by a 'getting too warm and defective' wire joint. It cannot report a wire not firmly attached to a receptacle connection screw. It can only report some failures. And most 'good' indications are really only 'might be good'.
What happens if a safety ground is missing but the furnace is making a ground via air ducts? (This from personal experience.) The outlet tester might report that defective ground as good because a metal sliver was just enough to make a light glow.
In one case, the outlet tester said everything was OK. Meanwhile the AFGI was detecting and tripping on a neutral to safety ground short. A human safety problem that the outlet tester could not see..
And finally, it cannot report anything beyond the breaker box where an open neutral eventually caused a house explosion.
No tool reports simple and that accurately. A user is always expected to know what that tool is and is not reporting. And a user must always know that no 'bad' does not mean 'good'. In the real world, there is always good, bad, and unknown/undefined. Does the outlet tester report all three? Yes. But only if you understand what it is actually doing. Most damning is something that everyone should appreciate. It does not report in numbers. Therefore it only reports the simplest and most obvious failures.
Lights say it is good? Then it might be - nothing more.
And in this particular case is a device that would wire into the breaker panel and sound an alarm (or at least light a light) if the voltage on the two legs differed by more than a certain amount, or if the voltage on a single leg was out of range. It's a device that could easily be mass-produced for under $10, and it would save thousands of TV sets, microwaves, etc every year.
> And in this particular case
> And in this particular case is a device that would wire into the breaker panel and sound an alarm (or at least
> light a light) if the voltage on the two legs differed by more than a certain amount, or if the voltage on a single
> leg was out of range.
Which would be common if open neutral problems occurred with any notable frequency. Open neutrals on AC service is rare. And would not detect a similar problem inside the building.
Meanwhile, the rule is simple. Do incandescent bulbs change intensity when appliances power cycle? Lights report a problem probably before that meter reported a failure. If the consumer ignores light intensity changes, then (my experience) he will also ignore that alarm. How many assume the car's check engine light or brake failure light should also be ignored?
Meanwhile, noted is another reason why the safety ground is so important. Maybe one in ten old homes are missing that important ground because the lights still work. That earth ground important so that an open neutral does not cause massive voltage differences that would harm appliances. More important than an alarm is the all so important earth ground. Only way to detect an earth ground problem: visual inspection.
In a standard residential installation open neutrals inside the building cannot cause the type of damage that is seen here, except for the rare "Canadian kitchen" setup.
And most homeowners (and, alas, many sparkies and linemen) are clueless as to the signs of an open neutral. It takes a bit of a technical bent to appreciate the problem (how many people can even comprehend the oppositely phased legs of a 240V line?), and your typical banker or store clerk simply can't do it.
With a 200 amp service, the classical earth ground is insufficient to prevent serious over/under voltage problems in the event of an open neutral, especially when the problem back at the pole transformer. (A good quality Ufer would probably do it, though.) But carrying that much ground current is a problem in itself -- the ground electrodes would erode rapidly due to electrolytic action.
> ... the classical earth
> ... the classical earth ground is insufficient to prevent serious over/under voltage problems in
> the event of an open neutral, especially when the problem back at the pole transformer.
Earth ground is not to conduct all that current. Earth ground is sufficient to conduct enough current so that destructive voltages do not exist. Light bulb intensity still changes - indicating a problem that should not be ignored. But voltage is not that destructive when earthing is properly installed.
Had that earth ground existed, then voltages would not have been so massive as to cause the gas line and meter to explode. A serious overvoltage and undervoltage due to a broken neutral anywhere between the house and transformer. A lesser under and over voltage when much of the current is also using earth. Had that earth ground existed, then the failed neutral inside a transformer would not have caused that gas explosion.
Are lights brightening or dimming when an appliance powers on or off? Then it is most likely a minor problem. But in rare cases, and because it can be so major, then a homeowner is seriously negligent to ignore it. Earth ground does not eliminate the problem. Only reduces it to safer levels.
Earth ground is sufficient to conduct enough current so that destructive voltages do not exist. Light bulb intensity still changes - indicating a problem that should not be ignored. But voltage is not that destructive when earthing is properly installed.
You gonna bet your life on that?
Are lights brightening or dimming when an appliance powers on or off? Then it is most likely a minor problem.
Precisely what most HOs think, right up until the explosion and fire.
Note, I'm not arguing that an open neutral detection device would be cost-effective, I'm just suggesting that it would be no less so than, say, AFCIs (which are very probably a big waste of money, yet still code).