Fuse box to CB Panel - logistics

[RichK]

Hi All,

I'm sure it's been asked a million times and answered, but I'm not getting any google hits on the specific point.

When replacing a fuse box with circuit breaker panel in a 50's house, how does an electrician mange to transfer all the cables from one to the other. They will not be long enough in most cases, even if the new box is put in the exact space.

There's nothing wrong will the existing cables in the house, but they would not be long enough to connect to anything else except the existing fuse box.

Can one install some sort of small terminal block box above existing fuse box and use it as an interconnection box, then jumper all the cables to the new CB panel?

Regards,

RichK

[Joe]

[Joe]

Common practice is to install new meter base, weatherhead and run new wiring to the breaker panel. Although old cables may look fine, they could well be undersized and not adequately temperature rated vs. current standards. The power company then installs a new service drop from the pole. Short of that, for whatever reason, it is easy and cheaper to unplug the meter and simply run new cable to the new panel than to install a junction box and splice in more wire. That would not be applauded by your power company in any event. HTH

Joe

[RichK]

This is being done.

But how do you transfer all the existing 10-14 ga wires from the existing fuse box, to the new panel. Even if located in exact same spot, the geometry is different and many of these will not be long enough. Is there a clever way to "extend" them :-) That is why I asked if a box with terminal strip can be used for this purpose. Such box could be physically located above present fuse box, to make sure existing cables would be long enough.

RichK

[Eric]

My memory isn't perfect since it was about 20 years ago, but in my grandparents' house it was done like this:

New CB panel (w/new service wiring) installed next to existing fusebox. Fusebox and CB panel connected together with 1 or more large (2"?) pieces of EMT.

The guts (fuses, sockets, etc. but not wires) of the fusebox were removed, effectively turning it into a junction box. Short wires were run from the CB panel thru the EMT into the ex-fusebox and spliced to the existing wiring going to the rest of the house.

Eric Law

[RichK]

Thanks Eric for a very sensible and to the point response. This is a v. good solution, when there is space in the immediate vicinity of the old fuse box.

If the case, where I want to locate the new panel a few (say 6') from the fuesbox, wondering if this is still allowable. A bit more wire, but the same principle. Reason: old fuse box is in a finished part of a basement and want to locate new CB panel in an unfinished part.

I'm also considering a small junction box with TB's that would potentially fit into existing space along with a new CB panel.

Regards,

RichK

Fusebox and CB panel connected together with 1 or more large (2"?) pieces of EMT.

effectively turning it into a junction box. Short

spliced to the existing wiring going to the rest of the

[Pete C.]

The norm for the installations I've been involved in is to install a decent sized pull box up high where all the existing house feeds can comfortably reach and connect from there to the new panel with conduit. The various circuits in the pull box are then connected back to the new panel with new individual conductors. To contain the wiring mess a ground bar can be installed in the pull box with a larger single ground conductor returning to the new panel. The neutrals all have to go back to the new panel individually as do the hots.

[Pete C.]

The distance between the pull box and the new panel isn't critical, if you want to locate the new panel 6' away that's perfectly fine. Don't use the old fuse panel as a pull box, spend the $20 for a new one, the inspector will be much happier with it. As with any pull box or junction box, it has to be accessible, so you can't bury it behind sheetrock in your finished space. You can get oversized covers for the pull box that will overlap the sheetrock for a flush / finished appearance.

Pete C.

[M Q]

I am curious about the requirement for the neutrals to all go back to the main panel individually. It is not immediately obvious to me why that would need to be. Do you know the rational and/or the electrical code section?

[RichK]

Thanks for your help Pete C,

So would I :-) In the case in point there are already two fuse boxes, one being an adder for A/C. So I want to consolidate. Am also assuming that a pull box might be a bit smaller.

sheetrock for a flush / finished appearance.

That sounds even better.

Am also curious, as to the requirement for the neutrals running separately from pull box to new panel. Obviously less work to run just one, as with the ground.

Regards,

RichK

[aemeijers]

Chuckle. In this house, when they had to move service entrance due to an addition and a upgrade to 150 amp, they gutted the old service panel and used it as a giant junction box, with floating splices and terminal blocks, and extended the runs ten feet sideways to the new service panel. I guess it met code enough to get the inspection sticker, but I'm not really happy with it. (Note that the work predates my ownership- no way would I have signed off on that as owner, even if it cost another several hundred to pull fresh wire on all or some of the runs, or put a longer pipe between meter base and old location, or make old panel location a subpanel fed off a new main panel.)

aem sends...

[Pete C.]

Don't have a code reference handy, but an obvious reason is that GFCI and the newly required AFCI circuit breakers require the circuit neutral to connect through them.

[Pete C.]

I Don't have a code reference handy, but an obvious reason for separate neutrals is that for GFCI circuit breakers if used and the AFCI circuit breakers now required for circuits serving bedrooms, the circuit neutral is required to run through the breaker so that the breaker circuitry can make measurements of neutral current.

[BillGill]

The obvious to me answer is that if you use just one neutral all of the current from all of the circuits winds up running through that one piece of wire. This could easily lead to an overload condition.

Bill Gill

[BillGill]

That seems to be the standard way to do it. That's what they did several years ago when I had my fuse panel replaced. They had to move the panel to the outside of the wall the fuse box was on because the fuse box was in a closet. The just extended the wiring using wire nuts in the old fuse box, which became, as you said, a giant junction box. Then they screwed the cover shut and marked it as a hazardous area. The inspector seemed to expect just that.

Bill Gill

[Stormin Mormon]

I some how remember something to turn aluminum wire into copper. You'd crimp the coupler onto the end of the AL wire, and the other side of the crimp had some CU wire coming out.

I'd have to guess a lot of short lengths of CU wire, wire nutted and taped to the existing wires.

[Stormin Mormon]

With 220 volt feed to the house, it's very possible that if each "leg" was running the same amperage, you'd have zero amps in the neutral. So, the neutral is only for the imbalance.

[BillGill]

But most of the circuits he is talking about are unbalanced 120 V feeds to lighting, and small appliances. Depending on the actual layout they might wind up bing highly unbalanced. On the average they will be balanced. But the average is only an average, you have to design on the assumption that everything will go the other way. It's called Murphy's Law.

Bill Gill