# What would cause an electric dryer to blow the main (not thermal) fuse?



## bleech1 (Sep 13, 2018)

I have a friend's GE electric dryer that stopped working. Started by checking the door switch, the main start switch and when those were good, I figured it was probably the thermal fuse. I took the small panel off where the cord connections are and there was a main fuse, the round kind, 1/4" diameter by 1 1/4" long, 30 Amp. 

Tested this fuse and it was bad. Could not find a 30 Amp like this locally so tried a 20 Amp fuse. This blew after a little while. Ordered the 30 Amp fuses, installed one, and it seems to be working for now.

What would cause this fuse to blow? I am assuming a short somewhere so I shook the dryer pretty well while it was running and it seems fine currently.

I know fuses do not blow without reason, so what should I look for next if and when this fuse blows again?

In case there is any question as to what type of fuse I am talking about, here is a link:

https://www.amazon.com/GBB-30-Actin.../4+30amp+fuse&qid=1552945241&s=gateway&sr=8-4


TIA for any insight.


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## jeffmattero76 (Jan 4, 2016)

You can usually find those fuses at an auto parts store pretty easily.

A fuse blows when too many amps go through it. A short (connection between hot and neutral or between hot and ground) causes a large amount of amperage to flow, which melts the metal inside the fuse and stops the flow of electricity. That is by design. If multiple fuses blow, you have a short somewhere.

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## jeffmattero76 (Jan 4, 2016)

The 20 amp fuse blew because more than 20 amps were traveling across the fuse. Again, that is by design. 

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## jeffmattero76 (Jan 4, 2016)

Look at the plate on the appliance. It will tell you the amp draw of the appliance.

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## bleech1 (Sep 13, 2018)

Yes, I know the fuse blew because of too much amperage going through it, and that is why it is there and how it works. 

Any idea why it would be getting too much amperage, as in, the most common place a short would be? Also, if there was a short drawing too much amperage, why would this problem be intermittent, and not blow the next fuse immediately? How does a short circuit situation come and go? Like I said in the OP, I shook the dryer vigorously to try to trigger this short and it was fine.


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## jmon (Nov 5, 2012)

bleech1 said:


> Yes, I know the fuse blew because of too much amperage going through it, and that is why it is there and how it works.
> 
> Any idea why it would be getting too much amperage, as in, the most common place a short would be? Also, if there was a short drawing too much amperage, why would this problem be intermittent, and not blow the next fuse immediately? How does a short circuit situation come and go? Like I said in the OP, I shook the dryer vigorously to try to trigger this short and it was fine.


It's great that you really want to get to the root cause as to what happened. I can't really give you a definitive answer as to why or what's going on in your particular situation. However, I can offer my thoughts on the situation.

About how old is the dryer? Fuses do go bad, get weak, wear out over time, power surges, etc. As mentioned, they are a safety device to protect the circuitry/other components etc, from further damage. They don't last forever and can burn out.

Bottom line, you got it working now, I would just keep an eye on it. If it keeps blowing fuses, it would definitely require further trouble shooting.


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## jeffmattero76 (Jan 4, 2016)

I have no idea what made the original 30 amp fuse blow. The 20 amp fuse was simply too small for the current draw of the appliance, do that is why it blew. You stated you have a new 30 amp fuse in it, and it is working as expected. I am not sure why you think there is a short. 

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## bleech1 (Sep 13, 2018)

jmon said:


> It's great that you really want to get to the root cause as to what happened. I can't really give you a definitive answer as to why or what's going on in your particular situation. However, I can offer my thoughts on the situation.
> 
> About how old is the dryer? Fuses do go bad, get weak, wear out over time, power surges, etc. As mentioned, they are a safety device to protect the circuitry/other components etc, from further damage. They don't last forever and can burn out.
> 
> Bottom line, you got it working now, I would just keep an eye on it. If it keeps blowing fuses, it would definitely require further trouble shooting.


Not sure of the age as it is not mine, but it looks fairly new. I would say in the last 10 years or so. Maybe that's not so new! ha.

I was thinking and hoping it was just a bad fuse. I replaced with a 20Amp that blew fairly quickly, but now the correct 30Amp is in place.

I guess it's possible that it draws 20 Amps on the regular and that is why the 20Amp fuse didn't last very long but that I cannot say for sure.

But you are right and I'm certainly not going to do anything if it keeps working but I was more interested in what would cause this and what to look for when/if the 30Amp fuse blows.

As you said, it definitely *could* be just a bad fuse that needed to be replaced but generally when a fuse blows, it is rarely because of a bad fuse in my experience.


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## jeffmattero76 (Jan 4, 2016)

I have no idea what made the original 30 amp fuse blow. The 20 amp fuse was simply too small for the current draw of the appliance, do that is why it blew. You stated you have a new 30 amp fuse in it, and it is working as expected. Why do you think there is a short?

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## Wiredindallas (Nov 9, 2018)

I did not know dryers had a fuse inside them. Maybe that's a 21'st century thing. I just bought a flat screen HDTV only because I moved to a 2 story house and my old working 36" tube type TV was too heavy to carry upstairs.
Back to this issue, the link is for a very fast acting fuse. A slow blow fuse may be better.


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## HandyAndyInNC (Jun 4, 2018)

There are many things that would cause this to happen. The motor being dirty, not enough cool air across the windings, Too many items in the drum that caused the motor and the heating elements to draw more current. The pulleys not as free turning as they once were, caused the motor to draw more current. Even a voltage increase, which in turn caused the current to increase. Or a resistance increase. Try making sure that the pulleys and drum turn easily. Ensure that all the ducts are clean and free of debris.Ensure that the plug is secure in the outlet. Ensure all of the electrical connections are tight and secured properly.


Andrew
Handy Andy In Mt Airy NC


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## Bud9051 (Nov 11, 2015)

As Wiredindallas mentioned the replacement link you provided says that is a fast blow fuse. You need to check the manual for that dryer to see what fuse type the require, fast blow seems strange for a dryer. Someone before you may have changed it without checking.

Bud


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## bleech1 (Sep 13, 2018)

Well, it blew again after a week and half of regular use. Maybe I should look into a non-fast blow fuse? The drum seems to turn freely so I am not sure what else it could be.


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## spitz1234 (Jan 1, 2019)

NON fuses should be used on the electrical heating elements as if they short it blows the fuses instantly. There is no inrush in a resistive load. If the fuses are also inline with a electric motor "resistive load" a non fast blow fuse will blow. 

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## DanS26 (Oct 25, 2012)

OP......have you checked the sag on the heating coils?


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## DanS26 (Oct 25, 2012)

DanS26 said:


> OP......have you checked the sag on the heating coils?


I'm surprised I have not received a response from the OP.

Sag on the coils will create the conditions the OP described.

So I'm posting again so that those DIY'ers that come across this problem of intermittent breaker trips on an electric dryer would check it out.

It's not intuitive.....you have to disassemble the dryer to find the problem.


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## bleech1 (Sep 13, 2018)

DanS26 said:


> I'm surprised I have not received a response from the OP.
> 
> Sag on the coils will create the conditions the OP described.
> 
> ...


Thanks Dan, I appreciate the info. 

Well, the update is my friend replaced the fuse a couple of times and the last time the fuse housing was actually melted! I thought the fuse was supposed to blow before that?

Anyway, she ordered a new housing and I put it in and it has been working but obviously there is another problem. If this was my dryer, I would have junked it but now I want to find the problem. It was not worth the $40 bucks she spent on the housing let alone all the trouble. But now I want to know (and fix it) for my own knowledge.

I assume I can access the heating coils by taking off the back panel? And by "sag" do you mean they are literally sagging and making a short circuit situation when in use? What would cause this on a fairly new dryer? I know the heating elements go bad but what is, and what causes, coil sag?

Again, thanks for the information, my friend.


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## DanS26 (Oct 25, 2012)

Normally the coils on an electric dryer are accessed by taking the front off and removing the drum.

Many YouTube videos on the how to disassemble dryers.

The sag is caused be the red hot coils drooping under there own weight when energized causing a short. Most of the time the coil is destroyed, but sometimes it will cause a short to trip the breaker but not break the coil. Then the coil cools and retracts. This can be an intermittent process.

It can affect even new machines if the coils are not properly installed at the factory. Only way to tell is to disassemble the machine and look for drooping coil segments.

Good luck.


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## carmusic (Oct 11, 2011)

it could also be cause by loose fusible in the fuse housing creating a loose connection (or loose connection to the fuse housing) and a lot of heat that transferred to the fuse itself causing it to blow even if under 30A load


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## bleech1 (Sep 13, 2018)

Update:

The dryer has been working fine all this time after swapping out the fuse housing.


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