big fuse problem

randallatha

I have a old type fuse box running to my water heater, the heater is a 2 yr old 40 gallon, the fuse box takes 2 old type fuses, not the screw in, i was useing buss one time non-20 amp fuses,they would blow sometimes about once a year or every 2 years, tonite one 20 amp fuse blew and I mean BLEW!, fire, sparks all coming from the fuse, It happened 5 mins after I took a shower, could it be a major fuse failure or is it the box, the wires look okay, I'm going to put in a breaker box but I need to find some one to wire it up first. the fuse that blew was put in there about 2 years ago. I am terrified to try and put another fuse in there out of fear of burning down my house
I'm not exaggerating, when the fuse went it was like the 4th of july, the burnt smell linger even thiugh its been 8 hours now, the wire is #10, AllanJ I have 8 fuses I can use all are 20 amp .
this is my water heater http://www.reliancewaterheaters.com/prod/e-606.html

Just Bill

My first guess would be that one of the heating elements shorted out. If the fuse block is burned, it will probably have to be replaced. Repair is usually a waste of time/money. Replace with breakers.

AllanJ

Did it blow first or were you tinkering with the circuit?

If you turn off the main breaker (or pull the main fuses), replace the blwon fuse, close the small fuse box, then turn the power back on, there will not be a fire hazard.

You need a lot of electrical know how plus equipment to prove that the circuit is not going to blow and waste the new fuse immediately upon replacement. Fuses cost money. For this reason it is a good idea to replace the small fuse box (a kind of subpanel) with a more modern breaker box.

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The disadvantages of crab apple trees. In summer, the apples are too sour to pick and eat. In winter the birds come and leave dropping all over the place.

Jim Port

Typical water heaters are wired with #10 wire and 30 amp breakers. What size wires are used in your installation?

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Answers based on the National Electrical Code. Local amendments may apply. Check with your local building officials.

awdblazer

what size of water heater do you have? as in watts not gallons

emolatur

I'm going with what I think Jim Port is chasing.

Most water heaters are on 30A circuits and 25A is typically what they want. I'm guessing your fuses blow once a year because you're running close to the limit.

The box itself is probably not the cause of your fuse's catastrophic failure - my guesses are as follows:

1. As someone else said, WH element shorted. Dead shorts cause more "entertaining" failures than small overloads.
2. Defective fuse to begin with.
3. You're exaggerating. (or you're just not familiar with the failure modes of some fuses, and took it as more than it really was.)

J. V.

I think the circuit is undersized for the water heater. Just like Jim says. 2 year old water heater and who knows how old the circuit is. Thats why you don't just install stuff without researching as to what is required to operate it.