Upgrading Fuse Box

I want to upgrade the fuse box in my home to a circuit breaker box. I actually assisted on this exact thing a couple of years ago, and thought the process was relatively simple. But when I went to the store to get the materials I know I needed, the salesperson started asking me all of these questions about which I had no idea, nd I left more confused than when I arrived.

Anyways, is there a guide to making this upgrade? Or has anyone done this recently and can give me some help? Thanks in advance.

 

Is the Service Dis-connect in a seperate enclosure?

 

Its not really that complicated, people just try to make something out of it that its not. Tell us more about it.

 

One thing you need to make clear is - Is the existing fuse box 100 amp? - Are you going to replace it with the same capacity? - If you plan on increasing the amperage availability - Then the power company will need to run larger wire in to your home and you will have to change the riser -weatherhead etc - Before we can help - we need the details.

 

Ok, I appreciate everyone's input. I spoke with the power company, and they say that the service is fully capable of running up to 200 amps. I'm putting a 100 amp box on, I'm not sure what's on there now. There are only 7 circuits for the entire house, so 100 amp box should give me more than enough. I have to pass a test by our city in order to get a permit to do it myself, and the power company will shut off the power with no problem, but won't reconnect it without a permit. But the test is a different issue.

I know that when I replaced the box before, it turned out to be a simple matter of labeling the wires, and transferring them to the correct spot on the new bus bars. And to have the service turned off above the box so that I can't kill myself that way. Any other information you would need?

 

We need to know what you now have because if its a 60 amp split buss type - Then you will need to change your service entrance - What the power company told you was - Their part is good for 200 amps - I doubt if yours is - You see - Most power companies only bring power to the weatherhead - From there down is your baby. Let us know. I guess by now - you may have a little more respect for a real electrician. Huh?

 

I've always had respect for them, just not money to pay them. How can I tell by looking at it what type of service it is?

 

Ok, I think this is a 60 amp box, so I will need to replace everything from the weatherhead on dow to the box. How's that for a starting point?

 

I would say that you are on the right track now - Are your main fuses (what we call Shotgun Shell type?) - If they are 60 amp - then that is all the capacity that you have.

 

There is one slot for what I think is the A/C that has 2-45 amp shotgun shell fuses in it. Other than that there are 2-S20 fuses (blue rimmed), and 4-S15 fuses (orange rimmed)

 

Another bit of information I found out. The inspector here in town requires 3 guage wire from the weatherhead to the box. I appreciate any and all help.

 

_-_-bump-_-_

 

If that's what your locality requires, then that's what you'll have to do.

#3 wire might be hard to find at the big box stores. But for a few more cents a foot you can just step up to #2.

From NEC 2002 Table 310.15(B)(6) for copper wire service to 120/240V, 3-wire, single phase, For SERVICE ENTRY wire ONLY:

#4 - 100A
#3 - 110A
#2 - 125A
#1 - 150A
1/0 - 175A
2/0 - 200A
3/0 - 225A
4/0 - 250A

I guess I could see your locality being paranoid and requiring one step up.

If you are going to go through all of the trouble to replace everything from the masthead to the panel, I would suggest simply stepping up to 200A service. The cost difference will be minimal. Typically this would require 2/0 wire, but if your inspector does require a step up then you'd need 3/0.

Now, on your old panel, you have only described the fuses protecting the branch circuits. You haven't described the mains. It does sound like a 60A service though.

(edit: as John points out, this table is not to be used for general ampacities, only service entries).

 

Just a word of warning about the table Mark presented. It is not a general purpose ampacity table. Although it does apply to the situation of this thread, its use is very narrow. Specifically, it cannot be used for subpanel feeders.