incoming power leg breaks

[kwired]

I didn't think about the response time. I guess you would have to trip in 0.06 cycles to be inside the CBEMA curve for 200% voltage. Perhaps in conjunction with UPS and/or surge protector would help dampen the overvoltage for long enough. I'll leave that up to someone else to look up.

Perhaps an isolation transformer is the way to go.

As I was reading through posts I kept thinking of voltage monitoring equipment and shutting down either by dropping contactors or shunt trip mains etc. then I saw your isolation transformer - probably the best idea. 240 volts in 120/240 out it won't care if there is an good neutral or not on the supply side. If you lose an incoming grounded conductor you will have no primary current and therefore no secondary voltage. They are a little expensive if you need to go over 15-25 kVA but if he has battled this for as long as he says - it probably doesn't look all that expensive compared to what has needed repaired/replaced in the past.

How about some preventative maintenance. Sounds like the equipment you require is a chainsaw.....cutting down the trees in the easement might help decrease the chances of this happening again.

Or have the POCO secondary put underground then you won't have to worry about trees anymore. Tree trimming gets forgotten about - until the next downed line incident, and they grow back faster then one realizes many times.

 

[PetrosA]

Moderator
You can close this post
I appreciate the few suggestions
At the same time for what it is worth
I did not come on here to be beat about the head and shoulders and be told how stupid or that I have no expertise
I can remember a few years back when this site was always helpful and never saw anyone put down or beat on
You are right I do not have the ability to go out and trouble shoot every little piece of the utility companies wiring
If it was a matter of simple trees and could be safely removed then yes, I would cut them
When it is out in an open area or it is at the transformer then I can't control that
I apologized for making the wrong statement of power and not the neutral
When you are slapped with the gift of Agent Orange and your world stops turning
Because of the leukemia, the kidney failure, the heart problems, the tumors in your throat
from all the medications you have to take then things do not always stay as sharp as they did
I thought I could come to an old forum and would be welcome back with a handshake I see that was not what happened
Mr. Mivey you seem to be wanting to get me in a position to argue with you so you can show how intelligent you are
I concede you are a far more talented person than I so you win
I continued to lament even after you mentioned it and I do not have enough sense to even talk to you much less anyone with more intelligence that both of us
I bid you a good day sir and leave you to now degrade someone else or continue to tell them things they do not need to hear
To the rst of You I thank you for your patience and your suggestions and answers

I honestly don't think Mivey was bashing on you. I see how you might have taken his comments the way you did, but I think what he meant was that you've obviously been letting the POCO know about this problem and have been dealing with it for a long time. I don't think he meant that you've been complaining about it here.

His comment about expertise has to do with how a given electrician deals with POCO representatives and is also not meant for you to take personally. It can have a lot to do with who someone knows at the POCO or how well that person understands the POCO hierarchy and how to navigate it or even how they communicate during a phone call with whoever they get on the phone. I worked for a guy who had absolutely no talent at getting the POCO to come out for emergency situations in a timely manner. There were times our customers waited for days to get power turned back on when he called it in. On the other hand, I was able to get a trouble call dealt with immediately, in hours, or same day at the latest.

The bottom line is that there is a reason your neutral keep breaking over and over. Determining what the reason is and convincing the POCO to deal with it correctly may not be so simple. It could be anything from a bad batch of triplex they used, to too many splices, an overly tight run, old poles, or a number of other reasons. As Mivey stated, the best thing would be if one of the forum members lived nearby to you and could help you get this resolved with the POCO. If you let us know what are you live in, maybe someone can give you a hand.

Good luck and all the best!

 

[mivey]

At the same time for what it is worth

I genuinly feel for what you are going through in your personal life. I am not your enemy but am trying to help you. PetrosA pretty much summed up my thoughts so I'll just ditto his post.

 

[mivey]

then I saw your isolation transformer - probably the best idea.

For an active solution I do too. Probably can get out for less than $5K in some parts of the country, maybe 2-3X that elsewhere.

Or have the POCO secondary put underground then you won't have to worry about trees anymore. Tree trimming gets forgotten about - until the next downed line incident, and they grow back faster then one realizes many times.

That would be a good solution if he can determine trees are the only problem and if the UG offered would get rid of all the exposure.

 

[winnie]

Another thing to keep in mind: lots of expensive electronic devices use 'universal' power supplies which are designed to operate on anything from 100-250V. Looking for this feature when you buy your electronics will give you devices essentially immune to this sort of failure.

-Jon

 

[meternerd]

Datashield S100

Datashield S100

I use a Datashield S100 "Super Filter" on my entertainment center, including a 55" flat panel TV. It trips at even slight sags and surges. We live in snow country, so power problems are not unusual. Costs $105 with a 6 ft cord and six receptacles. Not a UPS, just a very sensitive protector. Not a whole-house device, though. I am not impressed with those.

http://www.cnet.com/products/datashield-s100-superfilter-strip-6outlet-6ft-cord-10k-ins/

 

[mivey]

I use a Datashield S100 "Super Filter" on my entertainment center, including a 55" flat panel TV. It trips at even slight sags and surges.

Tripping for a 120% surge is different than tripping for a 200% surge. The difference in maybe 1/2 second clearing need vs 1 milli-second (see ITIC/CBEMA curves).

 

[meternerd]

Tripping for a 120% surge is different than tripping for a 200% surge. The difference in maybe 1/2 second clearing need vs 1 milli-second (see ITIC/CBEMA curves).

Seems like the OP was referring to a neutral problem. He was asking about a protective device. I have yet to find a whole house device that can protect against POCO issues such as open neutral, primary to secondary faults, etc. My suggestion was just that...a possible way to protect those things that are expensive to replace. POCO's are not usually very responsive unless it can be shown that a defect in the service was the cause of the problem. Trees, loose neutral in the service panel, corroded conductors, etc. are all reasons customers expect compensation when their stuff fries...but utilities are sometimes seen as the "Deep Pocket Santa Clauses" when customer equipment quits working. You'd be amazed at the "junk" that people bring in, convinced that the utility is the reason their stuff died. I'm NOT saying that the OP is in this group, but it's just my humble opinion that if you value your equipment, it's up to you to install whatever you feel you should to protect it. If the POCO is unwilling to fix a problem with THEIR equipment, they should be held responsible, but if customer equipment is shown to be the problem, why should the utility have to pay for their lack of foresight? OK....rant over.

 

[GoldDigger]

Tripping for a 120% surge is different than tripping for a 200% surge. The difference in maybe 1/2 second clearing need vs 1 milli-second (see ITIC/CBEMA curves).

SPDs are designed to clamp the voltage by absorbing energy for the duration of the spike or until OCPD opens. No MOV will be able to handle the excess voltage from a compromised neutral for more than a fraction of a second. The only method that can protect in the OP's circumstances would be a fast acting disconnect, maybe supplemented short term by an SPD.

 

[mopowr steve]

I look forward to the day Main breakers come with neutral loss detection that will trip and indicate such an event. The problem is to common and many times results in fire or near fire events.

 

[meternerd]

SPDs are designed to clamp the voltage by absorbing energy for the duration of the spike or until OCPD opens. No MOV will be able to handle the excess voltage from a compromised neutral for more than a fraction of a second. The only method that can protect in the OP's circumstances would be a fast acting disconnect, maybe supplemented short term by an SPD.

Yup...that's why I chose the Datashield. It doesn't suppress the surge/sag, it just trips the output, and it is FAST. I've had mine for years and have yet to even blow a fuse. Cheap protection. IMHO, as always.

 

[Tony S]

Many moons ago (about 35 years) I lived in a rural location at about 1200ft elevation. Lightening was a regular occurrence and I was well and truly fed up with answer phones, faxes, computers, etc being toasted.
The only surge suppressors I?d ever come across through work were for 11KV, not really suitable for home use but they gave me an idea.

I made a network of transorbs and varistors to go across the supply downstream of the incoming power company cut-out. A smaller unit for the phone line minus the varistors. Both units connected direct to the earth nest at a different point to the house MET.

I can?t claim it worked as intended but my phones, etc worked when the neighbours didn?t after a storm. We were on the same shared OH LV supply.

 

[mivey]

SPDs are designed to clamp the voltage by absorbing energy for the duration of the spike or until OCPD opens. No MOV will be able to handle the excess voltage from a compromised neutral for more than a fraction of a second. The only method that can protect in the OP's circumstances would be a fast acting disconnect, maybe supplemented short term by an SPD.

I wonder if there is a monster-sized SPD to go on a house that could handle line current for long enough? I'm thinking on the order of tens of KJ.

 

[kwired]

I wonder if there is a monster-sized SPD to go on a house that could handle line current for long enough? I'm thinking on the order of tens of KJ.

Even if so what assurance is there that you only see nominal 120/240 at the loads? The SPD is connected parallel to the load - shunt enough current when incoming voltage is high and you can have some control over what voltage is seen by the load but nothing really assures you will drop the voltage to a specific level either. And you still can have a transient voltage high enough the SPD just can't handle it, or in this case with the high capacity SPD maybe even the supply conductors are not capable of carrying enough current that the SPD is attempting to divert from the protected equipment.

 

[mivey]

Even if so what assurance is there that you only see nominal 120/240 at the loads? The SPD is connected parallel to the load - shunt enough current when incoming voltage is high and you can have some control over what voltage is seen by the load but nothing really assures you will drop the voltage to a specific level either. And you still can have a transient voltage high enough the SPD just can't handle it, or in this case with the high capacity SPD maybe even the supply conductors are not capable of carrying enough current that the SPD is attempting to divert from the protected equipment.

I think a high-voltage event will either be brief enough that the SPD might could handle it or it will be a high enough and/or long enough that there is not much you can do.

With a 120/240 voltage level we might could control it. If one leg moves from 120 towards 240 then the low impedance SPD shunt across the load might help push the voltage back towards 120 long enough for a switch to take out the circuit before severe damage occurs but it is doubtful a SPD would survive. It would seem we would need to move away from a typical SPD and employ some type of TOV protection device.

Not really sure what it available out there for lost neutral TOV protection. I guess a search is in order but I'm too distracted at the moment.