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In my detached workshop/garage, I have an old fuse panel servicing that building only. I am thinking about switching it out with a new small breaker panel. I have been reading everything I can find on properly making this switch, and for a while was referring to this as a sub panel, with the larger breaker panel in my house being the main. I made note of everything I read saying to make sure the sub panel's neutral and ground were not bonded/connected and the dangers that creates. However, upon further inspecting my setup it occurs to me that my situation is different.

The meter hookup is on the side of my log cabin meter hookup

Years back when I had electric turned on, the power company explained that my 1930s cabin had a really old service hookup: The rightmost meter services just my hot water heater. The left meter goes to my main breaker panel inside the cabin. On the left of that meter is a Square D panel, with a single switch inside that sends a buried line to my detached workshop.

Once inside the workshop, it runs through the pictured rightmost panel with an on/off switch in it (panel is opened up in this photo -- revealing there are 2 black hots and a bare wire neutral).
enter image description here

That switch panel (switch says 100 AMP on it) is then fed into the fuse panel. In the fuse box, the main pull out switch, when pulled out, shows that 60 amp fuses are installed. As you can see from this photo of the inside of the fuse panel, it is a bit of a mess, hence why I'd like to clean things up with a 6-8 breaker panel.

enter image description here

So am I right that this is not a 'sub panel' hookup, since it is coming right off the meter? It is essentially its own main panel in a different structure. I'm thinking I would get a new breaker panel and hook it up to the 3 service wires (2 hot, 1 neutral) present in the adjacent Square D box pictured above?

My comfort level with DIY electrical work is simple swap outs or replacements. If this is more involved I will wait to get an electrician to do it, but where I live up in the mountains, electricians aren't plentiful and you usually have to wait 6 months or more before one can squeeze you in for non-emergency service.

enter image description here [![enter image description here][5]][5]

[5]: https://i.stack.imgur.com/7bXQ4.jpg![enter image description here](https://i.stack.imgur.com/diL5I.png)

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  • You talk a lot about "switches" but I have a feeling they are actually circuit breakers. Can you clarify that please? You can edit the question to add info. – Harper - Reinstate Monica May 8 at 5:23
  • Where do the water pipe bond/ground rod wires (grounding electrode conductors) terminate in your setup? – ThreePhaseEel May 8 at 16:46
  • @Harper - Reinstate Monica Yes, I was being sloppy in my terminology. They are actually single circuit breakers from what I can tell. – NHCabin May 8 at 17:50
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    Your fuse box is a sub because the “switch” is the main. You will need a grounding rod(s) at the new panel, don’t go with a 6-8 breaker get a 20 all of your receptacles in the garage require GFCI protection in the 2020 NEC a 100-150 amp 20 slot will only be a few dollars more, I have never had a customer ask me to downsize a panel but I have had customers upsize multiple times. Since you have a main breaker, it is a simple swap out. Your feeder is aluminum so you will want to get a small tube of anti oxide compound like noalox and coat the wires, it can be used on copper also. #6 gnd to rod – Ed Beal May 9 at 16:16
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    @ThreePhaseEel Yes the two meters share an encloseure, not two seperate meter boxes side by side. I'm kicking myself that 1 month ago the power company was over after a windstorm when my voltage was fluctuating down to 104 volts, and they had the meter boxes open but I didn't think to take a peak -- would have been nice to confirm with my own eyes exactly how they're wired with the grounding rod. – NHCabin May 10 at 20:22
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Your fuse box is a sub because the “switch” is the main. (From Beal) Installing a sub service panel is a bigger job, but if you've installed new boxes before the principles are the same. Read the section in the code, and leave yourself enough space. Remember you need a separate circuit for the light above the panel. I would recommend you install at least a 20 breaker box. A box with more spaces costs only a little more, and it's astonishing how fast you use them up.

(If you don't already know you must turn the power OFF to work on it, get an electrician!)

Your best friend on this is the free online National electrical code at NFPA.org


Just by the way, the fuse panel you're replacing is an old Federal Pacific box. If you have other Federal Pacific boxes with Federal Pacific BREAKERS, run, do not walk, to replace those panels!!

FPE Stab-Lok Electric Panels Don't Need to be Inspected; They Need to be Replaced!

The problem with FPE Stab-Lok breakers is they don't trip when there's an overcurrent, and the breakers themselves have bad connections inside that can start fires in the service panel. The problem is particularly bad with tied double gang breakers- these ALMOST NEVER TRIP FOR AN OVERCURRENT!!

There are no safe replacement Federal Pacific breakers. The Federal Pacific box itself is defective. You have to replace the whole thing.

FPE Stab-Lok Electric Panels Don't Need to be Inspected; They Need to be Replaced!

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  • The issue with FPE that precludes just replacing the breakers is the bus "un-stabs" - which is where the circuit breakers attach to the bus. Not an issue on fuse panels. There was never anything to indicate FPE fuses as dangerous. – Harper - Reinstate Monica May 8 at 18:50
  • @VWFeature thanks for the links — will definitely read up on clearances if I go this route. And yikes on the FPE breakers—glad I have a fuse box! All other breaker boxes and panels in my setup are Square D. – NHCabin May 9 at 0:48
  • I just wanted to warn IN CASE he had FPE breakers. I had that experience, without the fire, fortunately! – VWFeature May 10 at 18:31
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This is mostly a simple job

The good news is that since your fuse box is a subpanel, fed from the enclosed circuit breaker on its right, changing this out for a new panel is a fairly simple job. You'll want a short 1.5" conduit nipple, some matching locknuts, and some 1/0AWG Al XHHW-2 wire to replace the length of SEU that connects the main breaker to the existing fusebox, in addition to a 125A, 24- or 30-space, main lug panel to replace the existing fuse box with, and separate grounding bars for your panel if it does not come with them from the factory. The hots and neutral from the existing panel are wired over to the main lugs on the new panel with the panel installed so that the lugs are at the bottom, with the conduit providing the grounding path and the bonding screw removed from the new panel.

From there, you can fit the appropriate breakers and wire up the panel. Once that is done, then we can move onto the other problem; namely, that the SE cable from the meter into the main breaker is missing the clamp that's supposed to be there. Unfortunately, fixing that will require the power company to shut power off at the meter, and may require an electrician depending on local Codes, so it's not so easy to address; the good news is that it can wait until you can get an electrician in (it's a problem, but not a critical one by any means).

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  • Since there is an on/off option right next to the meter before the buried line comes to the detached workshop, I shouldn't have any difficulty installing the proper clamp for the cable coming into the main breaker panel. For clarity - if the metal conduit would be my ground from subpanel to main, I currently do have 2 hots and a neutral running from main panel to fuse panel, but you're recommending i replace with 1/0AWG AL XHHW-2. I'm trying to understand the reasoning behind switching out the cable. Thanks! – NHCabin May 11 at 13:46
  • @NHCabin -- the old cable from the breaker to the fusebox is SEU, which has two hots and a neutral, but no separate grounding path. I'm recommending you replace it with individual XHHW-2 wires in conduit. Also, what amp rating is the main breaker at the meter, and was the run from the meter + main breaker to the workshop direct buried, or run in a conduit for its full length? – ThreePhaseEel May 11 at 14:09
  • The buried line was put in sometime prior to my moving into the property, but I've dug down on both ends at the conduit and never found an 'end' so hopefully it is conduit from end to end. Okay I get what you're saying on the wires -- I like that idea as well, having it all within conduit -- I live in red squirrel country and they occasionally get into my workshop despite my best attempts, so I like having everything protected from their chewing anyway. – NHCabin May 11 at 14:18
  • @NHCabin -- what size is the conduit containing the buried line? I actually need to edit this answer, BTW, since I didn't realize the culprit fuse box was at the workshop not the main house (my bad!) – ThreePhaseEel May 11 at 15:10
  • @NHCabin -- did I lose you...? – ThreePhaseEel May 14 at 0:09

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