So much for the super beast.

[mbrooke]

When I look for a bad neutral problem the first thing I do is to check if there is a GEC bond to a city water pipe that can mask a weak or faulty neutral, also cable and shielded phone drops can also add to masking a bad neutral as they are bonded at both the pole and the house, after turning of the main, I lift these connections and make sure that no one is in a proximity of an electrical appliance and a Earth reference point as the grounding can become energized above earth if there is a bad neutral and you load down one leg of the service as there will be no return path back to the source, after lifting the above points, I turn off all the breakers in the panel and any sub-panels, I turn on only the breakers on one leg of the service or I use a separate load such as was mentioned a space heater of at least 1500 watts, then and only then I take my voltage readings being careful to not make a path from anything bonded to the service neutral and earth or other grounding, if I get more then a 10% voltage drop, or even a difference of 100% between the legs of the service, I check to see if it is also at the meter, then I call the POCO and set up a time to be there so I can also lift the masking return paths I mentioned above so that their beast can do its job without the cable, phone shield or water ground or any other return paths that could be masking the bad neutral.

Yes it's a few more steps but that's what we are paid for and we should understand how to safely load only one side of the service after lifting any possible masking return paths that could otherwise let a lost neutral go unfound.

Keep in mind that a RG6 or RG11 cable drop can handle quite a bit of current before you will see a voltage drop, I have seen RG6 catch fire because of a bad neutral, but that was on a very overloaded 120 volt only service that the POCO had already tested with the beast and said it was a good neutral, I wasn't involved and the previous electrician didn't know to lift the cable drop bond at the service before loading the service down with a 100 amp load bank, luckily he put out the burning cable but the homeowner freaked out on him and I was called in.

Just remember that if the neutral connection is lost that doing the above will also bring all grounding of this house or building up to 120 volts to earth, so I can't say enough how much care you must take to make sure no one is in harms way when doing these kinds of test.

Thanks for your post, all excellent points! Obviously my mind shuts off after midnight:ashamed1:

I should have mentioned the best place to do it is at the meter socket with the meter pulled. To be honest, now that I think about it don't do it at the main panel at all, especially if the house has metal water pipes or a gas line. Even if the water bond is disconnected along with the grounding electrode that has the cable/phone bond there is still the furnace with its gas line and an egc running to it. Same thing could be said about a gas range with a 120 volt circuit or an electric water heater. If one was to load bank at the panel current will end up returning from the circuit leading to furnace through the cable's EGC, through the frame and over through the gas line. Same with the water heater. The #10 egc in the romex will carry power from the main panel through the water heater tank to the pipes and out the water main. The 60 amps of stray current may not hurt the gas pipes or water lines, but a #12 EGC in romex stapled across wooden floor joists would get real hot real fast. And truth is if enough parallel EGCs are present say a #12 to a dishwasher with a copper water line with a grounded water valve bracket, a #10 to a water heater with metal piping, a #14 to a gas stove, the furnace gas line, ect ect enough parallel egc paths would be present through the gas and water pipes it would mask and real results from the test.

Any way, reading what I just wrote on my prior post...:jawdrop: Apparently I need to stop posting so late, even Im frightened by what I wrote:happysad:


To the OP, don't do what a previously mentioned at the main panel, and even the meter socket requires caution. I left out a lot on how to do it right:slaphead:

 

[K8MHZ]

Thanks for your post, all excellent points! Obviously my mind shuts off after midnight:ashamed1:

I should have mentioned the best place to do it is at the meter socket with the meter pulled. To be honest, now that I think about it don't do it at the main panel at all, especially if the house has metal water pipes or a gas line. Even if the water bond is disconnected along with the grounding electrode that has the cable/phone bond there is still the furnace with its gas line and an egc running to it. Same thing could be said about a gas range with a 120 volt circuit or an electric water heater. If one was to load bank at the panel current will end up returning from the circuit leading to furnace through the cable's EGC, through the frame and over through the gas line. Same with the water heater. The #10 egc in the romex will carry power from the main panel through the water heater tank to the pipes and out the water main. The 60 amps of stray current may not hurt the gas pipes or water lines, but a #12 EGC in romex stapled across wooden floor joists would get real hot real fast. And truth is if enough parallel EGCs are present say a #12 to a dishwasher with a copper water line with a grounded water valve bracket, a #10 to a water heater with metal piping, a #14 to a gas stove, the furnace gas line, ect ect enough parallel egc paths would be present through the gas and water pipes it would mask and real results from the test.

Any way, reading what I just wrote on my prior post...:jawdrop: Apparently I need to stop posting so late, even Im frightened by what I wrote:happysad:


To the OP, don't do what a previously mentioned at the main panel, and even the meter socket requires caution. I left out a lot on how to do it right:slaphead:

Trust me, I know my way around panels and know how to stay safe. Thanks, though, for your concern.

The POCO won't let us into the cans unless they are out there with us. That didn't used to be the case.

I really don't like using the house for the load for obvious reasons. I read all the posts and get as much info as I can. Thanks for all the input, too.

I may not get to all the responses today. I have code upgrade class this week. The instructor is the retired electrical inspector for the city and a friend of mine. I'll run this by him as well.

 

[K8MHZ]

140310-2348 EDT

K8MHZ:

I would not think 150 ft would be a problem for you. Almost any wire would work that has some insulation and adequate mechanical strength. CAT-5, twinlead, enameled magnet wire, Belden 8723, and previously mentioned extension cord are possibilities. I believe you could use a 500 ft roll of something and roll off only what was needed. I don't think the inductance of the remaining coiled wire would present a problem.

A 1000 ft roll of Belden 8525 is about 100 mH at a Q of 3 at 1000 H. 100 mH at 60 Hz is about 40 ohms from a Shure Reactance Rule. Just on the bench with no large local current the overall, no filtering, induced voltage is about 1 mV. If you had induced voltage problems you could change the orientation of the coil. But you are looking for volts of difference on the neutral, and I don't think you will see any substantial error from an induced voltage relative to the 1 V level.

.

I forgot to mention that this would require me to do connect to the pole on someone else's property (the tranny is two doors down and on a private road) and then have to drag the wire across two driveways, several snowbanks and a chain link fence.

 

[K8MHZ]

I don't think this is a simple neutral issue either. You start out with 236V and under load that drops to 224V. In this area 236V is only seen out in the boondocks and, if I recall correctly, is pretty close to PECOs minimum tariff voltage (I think their tariff voltage is 228V). Your POCO's tariff voltage may be different.

If it were a neutral issue, I would expect the loaded L voltage to drop in relation to N, and the unloaded L voltage to rise above by a pretty large percentage - at least 15-20%. If it's a combination of neutral and undersized capacity somewhere, then loaded L should drop, and unloaded L should rise, but L to L voltage would drop somewhat as well. In your case L1 and L2 are staying within 5-7% of each other which leads me to believe that your neutral is ok, but capacity is low. The fact that your phase-to-phase voltage is dropping indicates that you either have too small of a transformer, too small a triplex, or both. Let us know what they find.

This is in a semi-rural area on a small lake. Her properties are at the end of a private road that has a dozen or so homes on it.

I don't know what our tariff voltages are, I couldn't find them on line. That would be good info.

I agree that this may be a multiple issue.

 

[mivey]

He pulls the meter and puts this cheesy thing called a 'Super Beast' on the tabs, turns it on and by looking at two crude analog meters he tells me the neutral is almost perfect.

Maybe a 20 amp load is not enough. The Mega Beast goes to 80 amps.

I know he is wrong about the bad neutral, but at least I can show him the sag.

Sure it isn't a bad line connection/conductor?

While he was doing his thing, I took voltage readings at the meter (there was room for a regular meter probe) and got my loaded voltage down to 109 - 116.

But what were the amp readings?

By now my sister has been without steady power for three hours and she is sick of it.

No doubt. And she is probably giving you the eye.

I told the linesman that and he said he thought it was the transformer

That makes no sense, at least for the unbalance, as you had balanced voltage at the tranny.

He told me the transformer was a 10kva and it should be a 20. This is for at least four homes. There may be a fifth one, I will check later.

Well that's something. At least the voltage regulation will be better.

So, what do you think is going to happen when they heavy up the transformer and don't look for the bad neutral (that is somewhere between the meter can and the pole) ?

The voltage will be higher.

Why would anyone use such a crude instrument for troubleshooting professionally? It looked like it was made from drain pipe and Radio Shack parts.

Because it is a simple 20 amp loading device with integrated meter and does not require anything complicated. It is much easier than hauling around and wiring in space heaters.

 

[mbrooke]

Anyone have a link for the beast? Or a good one?

 

[mivey]

Anyone have a link for the beast? Or a good one?

http://hjarnett.com/products/manufactured/

 

[mbrooke]

Trust me, I know my way around panels and know how to stay safe. Thanks, though, for your concern.

The POCO won't let us into the cans unless they are out there with us. That didn't used to be the case.

I really don't like using the house for the load for obvious reasons. I read all the posts and get as much info as I can. Thanks for all the input, too.

I may not get to all the responses today. I have code upgrade class this week. The instructor is the retired electrical inspector for the city and a friend of mine. I'll run this by him as well.

Not doubting your abilities, just shouldn't have mentioned removing the water bond without checking for things like cox and phone bonds. It is me who is mentioning things that are unsafe. Anyway I did not intend to doubt you, more myself being dumb. Some on else might read my thread like an apprentice and end up burning up the cable TV.

http://hjarnett.com/products/manufactured/

Thanks! This is why I love this forum!

 

[K8MHZ]

Maybe a 20 amp load is not enough. The Mega Beast goes to 80 amps.

That's what I thought.

Sure it isn't a bad line connection/conductor?

I suspected the compromised neutral because the voltage on one leg raised when the other sagged, and it raised higher than it read with no load on it at all.

But what were the amp readings?

None taken.

No doubt. And she is probably giving you the eye.

At least it wasn't the finger.

That makes no sense, at least for the unbalance, as you had balanced voltage at the tranny.

Agreed.

Well that's something. At least the voltage regulation will be better.

Well, talk is cheap. We will see if a new pig gets put in the poke or not.


The voltage will be higher.[/QUOTE]

Hopefully not too high.

Because it is a simple 20 amp loading device with integrated meter and does not require anything complicated. It is much easier than hauling around and wiring in space heaters.

Yeah, but the same company makes one that is 80 amps and has digital meters.

 

[GoldDigger]

Don't forget that a neutral voltage shift of the same size as the voltage drop in the ungrounded conductor is perfectly normal and not a sign of a high resistance neutral.
It is only if the neutral shift is higher than the drop in the ungrounded conductor for a single sided load or if both are excessive that you need to look at drop or transformer neutral issues rather than just overall sizing issues.
In fact in a circuit where a reduced neutral is allowed, you would expect the neutral voltage shift to be higher than the hot lead drop when an unbalanced test load is applied.

Tapatalk!

 

[mbrooke]

Don't forget that a neutral voltage shift of the same size as the voltage drop in the ungrounded conductor is perfectly normal and not a sign of a high resistance neutral.
It is only if the neutral shift is higher than the drop in the ungrounded conductor for a single sided load or if both are excessive that you need to look at drop or transformer neutral issues rather than just overall sizing issues.
In fact in a circuit where a reduced neutral is allowed, you would expect the neutral voltage shift to be higher than the hot lead drop when an unbalanced test load is applied.

Tapatalk!

Exactly! Often gets confused with a broken neutral. Actually, the reason why MWBC have less voltage drop over individual neutrals. If one was to load down leg A at 16 amps at 120 volts about a 5 volt drop might take place. Drop 16 amps on the other 2 phases and 115 volts will go up by a few volts. The other 2 legs will also see less drop then compared to all separate neutrals. Elegant way of keeping voltage drop at a minimum, just dont break the neutral:angel:

 

[JoeTroubleShoot]

I do troubleshooting work for a POCO and I would say that the beast is usually not helpful mostly because it does not add enough load, it's only really good for wide open faults. You have to remove the meter naturally dropping all the house load. What I do sometimes is put jumpers in the meter trough and then hook the beast leads up to the jumpers instead of plugging it into the meter trough and have the customer add some load. Then you get normal load plus the beast. Even then, the beast may not be helpful like others mentioned for various reasons.

If someone says they are having problems, I take their word for it and won't leave until everything that can be changed by one guy is changed(house/pole conn, service drop, transformer leads/connections). There is really not easy way of finding a high resistance fault with the tools that we have, so just doing everything possible fixes 99% of the problems.

Also, the beast does not check the load side of the meter trough and it does not differentiate between a bad conductor and a bad line lug connection so you usually have to pull out a digital meter and test if there's a difference between the lugs and the wire.

They do make a mega beast, which I believe let's you add your desired amount of load up to 80 amps which is much more helpful. The Super Beast is really only decent for when people are not home and you can not add normal load. People always call in flickering lights and then leave.

Anywho, long post, but the best method is customer load and a lot of testing, if that goes nowhere then the next step is change everything that is questionable and put a long term recorder on the meter. Making 150 foot test leads is crazy.

Electricians call us a lot and a good amount of the time we find the problem in the meter trough or in the panel, so it goes both ways. Nothing I hate more than either POCO troublemen or electricians showing up and testing 120/240 and saying it's all set for a flickering light call.

 

[mivey]

I suspected the compromised neutral because the voltage on one leg raised when the other sagged, and it raised higher than it read with no load on it at all.

Not a clear indicator of a neutral problem.

But what were the amp readings?

None taken.

Load balance needs to be determined.

 

[mivey]

Don't forget that a neutral voltage shift of the same size as the voltage drop in the ungrounded conductor is perfectly normal and not a sign of a high resistance neutral.
It is only if the neutral shift is higher than the drop in the ungrounded conductor for a single sided load or if both are excessive that you need to look at drop or transformer neutral issues rather than just overall sizing issues.
In fact in a circuit where a reduced neutral is allowed, you would expect the neutral voltage shift to be higher than the hot lead drop when an unbalanced test load is applied.

Tapatalk!

Exactly.:thumbsup: And that makes the unloaded leg voltage referenced to neutral increase.

 

[wyreman]

It gets used daily around here to locate where the neutral is broken. One of the more useful tools invented.

I agree!

 

[wyreman]

109 volts doesn't sound that low to me.

2 boards go bad. One cause is that they replaced with a defective board (no quality control) or there really is a problem with the furnace and the guy isn't smart enough to trouble-shoot.

If two guys say there isn't a ground and you know there is one that should tell you something. Sounds like standard BS when they don't know.

We plug those control boards[when they are on expensive equipment] into isolation xfmrs.
Voltage regulation is also important because as the voltage browns, the board gets hotter.

Right now we have had good results w the tripplite equiv isolation xfmr
For voltage regulation: manufacturers "allow" 10%.
While 5% is recommended
We set our 480 phase loss monitors for dropout at 440 & 520

http://www.hiwtc.com/products/kleen...olation-xfmr-power-condition-463368-46241.htm

INPUT 120 Volt 6' / 5-20
OUTPUT 120 Volt 20.0 A; 2500 W
4 Sockets; NEMA 5-20; 15A/20 A
78/35.4 (lbs/kg)

Kleen Line Isolation Transformers - Power Conditioners for Ultimate System Protection; Eliminates ground loops, ground line noise & interference
SPECIFICATIONS;

IsolationIndependent input/output transformer windings Faraday Shield adds Primary - Secondary isolation Common mode noise 0.5 VoltDifferential mode noise 10.0 Volts
Industrial Grade, 9 Stage, 58,500 Surge Amp Spike / Surge Suppressor; 1 pico-second response
(The competition .......has only 1 Stage, 6,500 Surge Amp Suppressor with a dismal 1,000 pico-second response)
Noise & Interference Filter (Not Included in Most Competitive Units)
Inductor-Capacitor designEMI/RFI Noise rejection: 30 - 65 db; 10 KHz to 50 MHz
CoolingConvection
3 position User Select Terminal for Maximum Ground Loop Control

PERFECT FOR SYSTEMS SUFFERING FROM LOW QUALITY POWER


Power fluctuations and electrical noise: The water heater?s control system requires a source of stable clean electricity for proper operation. Connecting the water heater to a branch circuit that is subject to fluctuations in voltage level or electrical line noise such as emI (electro magnetic interference) or rFI (radio frequency interference) may cause erratic control system operation and malfunction. A high quality power supply filter/suppressor such as the kleen Line model SeLF/T-10 Series SC-L or equivalent must be installed if the above conditions exist.

 

[Smart $]

Not certain if it has been mentioned because I did not read all the posts... but I believe a common cause of furnace board failure is power line surge.

 

[GoldDigger]

Not certain if it has been mentioned because I did not read all the posts... but I believe a common cause of furnace board failure is power line surge.

Q: Do you know how many furnace techs it takes to change a flat tire?

A: It takes five. Four to lift up the car and one to swap tires until he finds the one that is flat.

 

[Smart $]

Q: Do you know how many furnace techs it takes to change a flat tire?

A: It takes five. Four to lift up the car and one to swap tires until he finds the one that is flat.

Hmmm... :blink:

 

[GoldDigger]

Hmmm... :blink:

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