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Replacing old fuse box questions

Posted by paulmars (My Page) on
Thu, Aug 26, 10 at 17:33

The 2 mains are both 60amp fuses. The power company wont tell me what amperage service I have, They say they dont know. How can I tell? I could just use 60a mains in the new breaker box, but if my service supports more, I'd like to get larger. I've never blown a main.

Also, all 115vac circuits are 15a, is that normal for a house built in 1954? Reason I ask is because I have 12awg wires coming out of the box and someone said I could replace all those 15s with 20s.

Oh yea, the reason I am changeing this is because:
1-a sub panel was added to the house before I bought it in 1986. It has breakers for the central AC and water heater. The AC breaker is loose and sometimes sparks when it cycles on. The bar that the breakers attaches to is damaged. It has always made me uncomfortable.

2-Since 1986 I have spent maybe 100$ in fuses. Less so these last few years since I cut two existing circuits in 1/2 and added two more fuses. There were two empty places on the box which is now full.

3-I want to add another circuit.

4-I cant use the clothes washer spin cycle when the central heater is cycled on, otherwise a 15a fuse pops. The AC is 230, the fan and heater are 115.


Follow-Up Postings:

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RE: Replacing old fuse box questions

Are you hiring an electrician to do the change out? If so, he will easily be able to determine if your service entrance wires are the proper gauge for a larger service.
If the service drop is the original from 1954, then more than likely it will only support 60 amps. However that being said, if you are going through the trouble of changing out the panel, you may as well spring for a new service drop that can support a minimum of 100 amps. Given you have an electric water heater and central a/c, I would go with a 125 or 150 amp service. If your budget is tight, then at the very bare minimum I would change out the sub breaker panel with the damaged buss bar. Sparking and loose connections have the definite possibility of starting a fire.
As far as using 20 amps fuses, if you are 100% certain that all wiring on a circuit is #12 gauge, then 20 amps is acceptable. I would be surprised though if the builder used #12 for all circuits in 1954 though. Good luck.


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RE: Replacing old fuse box questions

I agree with Scotty. This panel wasn't sized for the load you have today. I'd redo the panel with something mechanically and electrically sound, modern, and that can handle the circuits you want/need *AND* increase the service.

As Scotty says, just because there's 12G coming out of the panel, doesn't mean the entire circuit was wired with that. If you get the problem 15A circuits fixed (move the washer or heater to their own circuits or both), you'll probably not have too much problem with keeping them all at 15A. I've got an older house as well, and the only thing that trips the 15A circuits was the darling daughter using her high powered hair dryer.


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RE: Replacing old fuse box questions

You have 60A service. The utility (aka "POCO") will come hook up after the electrical inspector signs off. They will replace the service entrance cable if necessary.
I upgraded from 60A to 200A 2 years ago, and the POCO used the same 30-year old wire. Wires hanging in free air are rated to carry more current than when they are confined in raceways or walls. That is why you'll often see puny-by-comparison utility wires connected to much larger service entrance wires.


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