House electrical issue

[supton]

Originally Posted By: Pop_Rivit
Originally Posted By: dja4260
Originally Posted By: user52165
How old is this house and the wiring? Fuses?

Retrofit your home with circuit breakers, GFCI, and have all the wiring checked by a licensing electrician.


Electrical is new. Stove is also 220v with no issues that I know of. My electrician is licensed and experienced. Please read my post.


You keep saying that the "electrical is new", but then you're talking about fuses and 100 amp service. If the electrical is "new" then you should have circuit breakers and at least 200 amp service. Fuses and 100 amp service tell me you have an old electrical system that has been patched together.

There is nothing "new" about a residential system so old it still uses fuses.


I have a modern breaker panel (not sure if it is 200A), all new wiring--and the original 60A service. Prior owner redid all the wiring 15 or so years ago, but never got around to having a new service done. Neither he nor I have had a need for more amps, hence a 200A(?) panel with an old 60A service.

I cannot imagine putting in new wiring yet reusing a old panel with fuses; but if it was working, why not save a buck and reuse the old panel? code permitting, of course.

 

[dja4260]

The old 40 amp screw style fuse panel was replaced with a modern 100 amp breaker panel. I choose NOT to go with 200 amp as it wasn't necessary and required our electrical supply to come out and run a new line at great expense. The single sub panel located 3 feet from the dryer was left and the new wiring was run through it. All wiring with paper/cloth was replaced.

Sorry if I hadn't made myself clear. Wiring is new and up to code.

Moving on....

 

[SHOZ]

Don't most electric dryers use one leg for the motor and the other for the electrical heating element?

High voltage can be a bad neutral issue too with a 240V circuit.

My house runs 124v per leg,

 

[doitmyself]

dja4260,

Thanks for sharing your intriguing problem. Please follow up when you get it diagnosed so we can all learn from this.

My electrical knowledge is limited, but when I googled "too high voltage in house", the links indicate that your electrician did not follow through with proper diagnostic techniques.

It seems he should have measured the voltage of each leg, maybe indicating a neutral problem, but maybe not explaining your 256 reading, which seems to be just on the edge of too high. A neutral problem causing one leg to be high might be causing problems?

It seems the next diagnostic procedure not done was to read the voltage coming into the house service, which might indicate a power company (transformer?) problem.

Either call your electrician back or call the power company, which should not involve a charge...I think.

Good luck and keep us posted.

 

[kschachn]

You need to check the voltage at the main wires coming into the breaker box and see what you read there. Your voltage is about 128v to ground which is about 10 volts higher than mine. However, it may or may not be considered excessive by your utility (but I tend to think it is), and if you read this at the box then only your utility is going to be able to affect it.

 

[rjundi]

Originally Posted By: dja4260
The old 40 amp screw style fuse panel was replaced with a modern 100 amp breaker panel. I choose NOT to go with 200 amp as it wasn't necessary and required our electrical supply to come out and run a new line at great expense. The single sub panel located 3 feet from the dryer was left and the new wiring was run through it. All wiring with paper/cloth was replaced.

Sorry if I hadn't made myself clear. Wiring is new and up to code.

Moving on....


The confusing part is the glass fuses popping. No modern code allows for them in a panel nor do home insurances.

 

[JTK]

Sorry if I missed it above, but one of your two main leg fuses is what blew?

Was something (120VAC) in your home that draws relatively high current trying to run at the same time as the dryer? That being the case, it's going to take out the fuse for what ever 120V leg it's on.

 

[eljefino]

It sounds like the subpanel exists to turn the 40 amp 240V service into 30 amp to match the dryer plug which will have some sort of NEMA classification.

It's my understanding this isn't even all that necessary. Why not ditch the subpanel and put a 30 amp breaker in at the main box? If nothing else this will help keep you from eating expensive glass fuses as you sort this out.

Does anything else run off this subpanel? I think no. If you do have a heavy load elsewhere on this panel and/or a poor neutral it can cause havoc. It may be worth pulling the cover and looking for mystery wires (particularly a "purposeless" 12 ga romex) heading off.

 

[HerrStig]

Originally Posted By: JHZR2
256 is high to me (as that means each split phase is 128v), and into a fixed resistor, will draw more current as it will dissipate more power.

Remember that P=V*I and P=R*I^2, so, R*I^2=V*I, which means also that I=V/R

What that all means is that into a fixed resistor, a higher voltage will dissipate a higher current, causing a higher power draw. So 256V creates a higher current flow that blows the fuse.

The question is why would you have 256V at your home, out of the blue?

The other situation could be that the reading was wrong, you have an appropriate voltage, but the resistance of the heater element has DROPPED... Meaning that from I=V/R, a smaller value of R will also raise the value of I for a given (constant) voltage.
Filaments, as I recall from the tube days, draw more inrush current at start up than operating current which might account for the the fuse in one leg blowing.

 

[SHOZ]

Old fuse get weak and will blow. Especially if they are ran at near limit.

 

[dishdude]

High voltage isn't going to pop a fuse. There is a short in the wiring for the subpanel, dryer or something bad in the dryer like a heating element.

 

[HerrStig]

Originally Posted By: kschachn
You need to check the voltage at the main wires coming into the breaker box and see what you read there. Your voltage is about 128v to ground which is about 10 volts higher than mine. However, it may or may not be considered excessive by your utility (but I tend to think it is), and if you read this at the box then only your utility is going to be able to affect it.
Sounds like an unbalanced load, leg to leg. Perhaps a 120 load grabbed off one side of the drier line. Watching Homes on Homes has shown me some REAL wiring horrors. Things like wire nut splices inside a wall with no junction box.

 

[zzyzzx]

Originally Posted By: bullwinkle
256 on a 240 volt circuit is high-but not extremely high.


I also would not worry about this, especially on en electric dryer.

 

[sleddriver]

Originally Posted By: dja4260
The lint trap & air exhaust are both clean. The unit is less then 1 year old, front loading unit. It never heated very well and we're very unimpressed with it's drying ability.
Then the dryer outlet vent may be undersized. For example, a local builder decided 4" PVC was sufficient for a dryer. No, it isn't. A dryer blower is HVLP (high volume, low pressure). The longer it is, the bigger it needs to be to counter excessive flow resistance. Depending upon how long your vent is, lint (from your previous dryer) may have built up. A quick test is to disconnect the dryer and use an electric leaf blower stuffed into the vent pipe. I do this periodically to clean mine out. Amazing what comes out!

With the dryer disconnected from the vent pipe, turn it on and note the air temp and how much flow you get. If the flow is low, then perhaps the internal pipe is only partially connected? Loose? Something's blocking it inside (you never know, even new....)

Re: Fuses: They do age over time. Also check to be sure the fuse base and socket is clean, with no corrosion. They should be shiny bright. REMEMBER TO CUT THE POWER BEFORE CLEANING THE SOCKET! Use steel wool or a Scotch-bright pad. Your higher line voltage could also contribute to shortened fuse life. You can feel (carefully) for a warm/hot fuse or better, use an IR thermometer. Be advised they don't work on shiny (glass) surfaces though, so aim it at the metal and take multiple readings.

I am assuming your electrician checked to be sure the fuse size is appropriate for your new dryer?

 

[dja4260]

Originally Posted By: sleddriver
Originally Posted By: dja4260
The lint trap & air exhaust are both clean. The unit is less then 1 year old, front loading unit. It never heated very well and we're very unimpressed with it's drying ability.
Then the dryer outlet vent may be undersized. For example, a local builder decided 4" PVC was sufficient for a dryer. No, it isn't. A dryer blower is HVLP (high volume, low pressure). The longer it is, the bigger it needs to be to counter excessive flow resistance. Depending upon how long your vent is, lint (from your previous dryer) may have built up. A quick test is to disconnect the dryer and use an electric leaf blower stuffed into the vent pipe. I do this periodically to clean mine out. Amazing what comes out!

With the dryer disconnected from the vent pipe, turn it on and note the air temp and how much flow you get. If the flow is low, then perhaps the internal pipe is only partially connected? Loose? Something's blocking it inside (you never know, even new....)

Re: Fuses: They do age over time. Also check to be sure the fuse base and socket is clean, with no corrosion. They should be shiny bright. REMEMBER TO CUT THE POWER BEFORE CLEANING THE SOCKET! Use steel wool or a Scotch-bright pad. Your higher line voltage could also contribute to shortened fuse life. You can feel (carefully) for a warm/hot fuse or better, use an IR thermometer. Be advised they don't work on shiny (glass) surfaces though, so aim it at the metal and take multiple readings.

I am assuming your electrician checked to be sure the fuse size is appropriate for your new dryer?



Well the dryer has 40 amps of fusing at the panel, and two 30 amp fuses at the sub panel, one per line.

 

[tom slick]

A bad neutral causes one leg to go high and the other to go low; total voltage stays the same. If the voltage is actually high then it is supplied from the provider high. Nothing in the house wiring can make it higher than what is supplied.

 

[eljefino]

^ Yup but since high voltage crammed into a resistive load will increase current, we have to look for unbalance, or at least get the whole picture. Maybe the dryer set on "low heat" taps the neutral for 120 and the element has a defect, while "some genius" tapped the subpanel for a window AC unit we don't know about yet that just got activated for the summer. Remember it's only blowing one fuse at a time.

I'm still baffled as to why a subpanel exists with a larger breaker upstream; I think someone thinks it "has to match" the dryer outlet rating.

I'd like OP to pull the cover to the subpanel and get us a pic of what's going in there. Then kill all the other breakers in the house and run the dryer, counting the meter spins with a stopwatch to compute his power draw vs the ratings.

 

[SHOZ]

The only electric dryer I ever worked on was 120v for the heater element and 120v for the motor. I don't know if there are models that are true 240v rated. A true 240v setup would not need a neutral.

I had the neutral wire at the transformer on the pole get loose and the voltage in the house whet really high. Up around 160v per leg.

 

[HerrStig]

Originally Posted By: eljefino
^ Yup but since high voltage crammed into a resistive load will increase current, we have to look for unbalance, or at least get the whole picture. Maybe the dryer set on "low heat" taps the neutral for 120 and the element has a defect, while "some genius" tapped the subpanel for a window AC unit we don't know about yet that just got activated for the summer. Remember it's only blowing one fuse at a time.

I'm still baffled as to why a subpanel exists with a larger breaker upstream; I think someone thinks it "has to match" the dryer outlet rating.

I'd like OP to pull the cover to the subpanel and get us a pic of what's going in there. Then kill all the other breakers in the house and run the dryer, counting the meter spins with a stopwatch to compute his power draw vs the ratings.
Agreed on the "extra" fuse panel purpose ? AND on the potential unbalance. If ANY part of the wiring to the breaker is rated at 30 amps the breakers in the house panel SHOULD be no larger.

 

[SHOZ]

Fuses and breakers are for protection of the wiring and should be sized according to the wiring. If device protection is needed that is usually done on the device.

But I'll agree that the old fuse panel, if it is protected by an individual circuit breaker in the new panel, is not needed and is a potential problem. When I put the new 100A panel in my house I used the old 4 glass fuse box for a junction box to tap into the existing house wiring.

If the old fuse box is not protected then a smaller circuit breaker box can be put in for the cheap to replace the fuses.