Old subpanel and temporary needs

[manoweb]

This is the situation:

• the house has a 100A main single breaker outside, mounted next to the meter.

• This goes directly to a subpanel inside the garage that feeds the whole house. It is an old sub-panel from the 70's that is almost full but more importantly, it's hard to find breakers for.

I am in the process to build a detached garage and to request a service upgrade. For this reason, I want to find a solution that is fully up to code but is limited in scope: my immediate needs are that I need to run the welder, milling machine, CNC plasma cutter and compressor (and 120V stuff) in the *existing* garage. I need that equipment to build the detached garage and some other structure I've designed and fully permitted, so it's a chicken and egg problem.


In practice, I'd like a second sub-panel next to the existing one so that I have all the circuits for the equipment above. It all sounds relatively easy and not even that expensive as I can get a 100A sub-panel from a reputable manufacturer for around 50 dollars and each 30 or 50A breaker for ten dollars each.

The real problem I'm facing is - how to feed the new sub-panel. Normally I'd have a dedicated breaker in the existing sub-panel to feed the new daisy-chained sub-panel. However it seems like breakers of this old brand are only available from sketchy vendors at a steep price. I really do not like this solution.

What are my options? Ideally I'd have the breaker in the new sub-panel, downstream of the single main outside, somewhat bypassing the existing sub-panel.

 

[Norcal]

If the breakers are hard to get or expensive, like Zinsco/Sylvania, or FPE, your panel needs to be replaced, you never mentioned who the manufacturer is but if it either one of those, they have enough problems that the sooner it's replaced the better.

 

[TRWham]

Swap the existing subpanel feeder to the new panel then feed the old sub out of the new one.

 

[Terry D]

Is this just a temporary thing to get your garage built. So this equipment is going into your existing attached garage. And eventually you are going to do a service upgrade so you can run power to the new detached garage.

If this is all correct and all this temporary stuff will be coming back out when you upgrade the service. I wouldn't spend alot of money on it. What kind of panel do you have? Ebay has breakers. Do you have room in your existing sub to add a 2-pole breaker. Pictures would help

What do you mean about trying to bypass the existing sub panel

 

[Innovate1]

Why not just replace the old sub panel with a bigger one? Probably cheaper than whatever you need to do to add a subpanel off the old one. I don't follow the whole plan to add a detached garage and what you need as temporary. If you could sketch up some drawings showing the current layout of panels and final layout that would help a lot.

 

[manoweb]

Well I did attach a crude schematic to the original post but it does not show up. Direct link:

https://i.imgur.com/8rsUi7l.png

I know that the existing panel should be redone - however that is exactly what I do not want to do now as I will completely convert the old garage to living space once the new detached one is up, and I'll have to remove it completely and do it all over again. All the equipment I mentioned will be moved to the detached garage once it is up. I just want to do something safe and up to code but cheap, quick and temporary for now, so that I can get construction going. Ideally I'd like to be done with this by the weekend re-doing the whole existing sub-panel is what I specifically want to avoid.

Now, the existing sub-panel is a federal pacific. I did not mention it before because I know it's a shame but I'm aware of the potential danger. Yeah I could find a 100A breaker on ebay but I was wondering: if I put a breaker downstream on the new sub-panel, can I use polaris taps or some other form to avoid the installation of a breaker in the existing sub-panel? Everything is always protected by the upstream 100A breaker.

I also add a somewhat old photo of the existing panel: this was a work in progress to cleanup those unused wires at the bottom so don't mind those.

https://i.imgur.com/v2g9L68.jpg

(not sure what I am doing wrong but I cannot add in-line images)

 

[Innovate1]

What's your final power setup going to look like? Do you want 2 breakers at the meter, one feeding the garage and one the house? This is a bit beyond me so I will leave it to others....

 

[manoweb]

Finally I'll have a main distribution center with several breakers, one will go to the detached garage, one or more to the house, another to the outdoors kitchen. Then each environment will have it's big sub-panel. But for now I just want to have four 240V outlets so that I can run my things

 

[manoweb]

I'd say - forget what I will do when the detached garage is up, I have my ideas pretty clear about that. Now I just have this sub-panel I want to extend temporarily, and I am specifically trying to find a way without modifying the existing one too much.

I'm reading that in-panel splices (or, taps, I am not sure about the terminology) are in fact allowed...

 

[rlitman]

...Now, the existing sub-panel is a federal pacific. I did not mention it before because I know it's a shame but I'm aware of the potential danger....

Since we're discussing this, I don't believe you are aware of the potential danger. Two-pole FPE breakers do not trip. Period. Not, like they don't trip sometimes, or they trip at too high currents. No. They're well known to be switches and not breakers, so they offer you ZERO protection.

Who makes your outdoor panel? Please tell me it's not an FPE also.
Do you have any 240V loads in your inside panel (a range, dryer, water heater, etc.).

Anyway, just swap out your interior panel now, with something sufficiently large. This is a relatively easy DIY project, because you have a main breaker in the exterior panel you can use to safely disconnect the inside.

Get a really large cable trough. One large enough to take all of your old panel's wires and handle the splices, and connect that to the supply side (top?) of your new panel. And pick a new panel with lots of extra space, so you don't need two adjacent panels.

 

[manoweb]

Changing the existing panel is out of scope for this project. But yet one more reason NOT to add a Federal Pacific breaker out of Ebay into the existing panel. I need to check the outdoor panel but that is also getting changed soon anyway - just not this week.

Unless I find out that it's now allowed by code, I'm thinking to splice the current wiring inside the existing panel with three way polaris connectors and feed the new sub-panel out of that. With about 100 dollars and a couple of evenings of work I should be in a shape to start working...

 

[manoweb]

Ahah I had a look how much those polaris connector cost to splice #2 aluminum, and it's probably cheaper to re-do the whole panel You may be right rligtman, maybe the easiest is to just re-do the house panel

 

[rlitman]

Ahah I had a look how much those polaris connector cost to splice #2 aluminum, and it's probably cheaper to re-do the whole panel You may be right rligtman, maybe the easiest is to just re-do the house panel

The parts add up fast, and adding an adjacent panel next to a time-bomb just doesn't make sense to me.

BTW, with a nicely large trough to work in, you don't need Polaris connectors. They are really nice, and they do make future service easier, but for a permanent connection, they're not necessary. For the big wires, you could use split bolts and tape, or there are lugged aluminum connectors that you could wrap in heat shrink.

Also, if you use split bolts (the cheap option) to splice the #2 now, there's no reason you couldn't put in a 200A panel now, and upgrade the service to match it in the future. In fact, you could even put a 200A main breaker into it, since the breaker in the exterior panel is what's protecting it's feed.

 

[manoweb]

but why would I need a main breaker at all into a subpanel, provided there is an upstream breaker. Yeah it makes it easy to remove power at once, but the incoming wires are still going to be hot, so to work safely one has to walk to the upstream panel.

 

[wyliesdiesels]

but why would I need a main breaker at all into a subpanel, provided there is an upstream breaker. Yeah it makes it easy to remove power at once, but the incoming wires are still going to be hot, so to work safely one has to walk to the upstream panel.

if the subpanel is in a detached structure, code requires a main if there is more than 6 breaker handles.

 

[manoweb]

Advice on which big panel to buy? I want the biggest one with the most circuits available.

 

[Norcal]

Advice on which big panel to buy? I want the biggest one with the most circuits available.

Anything other then Eaton BR, or GE, my preferred panel is Eaton CH, then Siemens, SQ D QO, not terribly fond of SQ D HOM, because it's built with a aluminum bus & I prefer copper bussed panels. It used to be 42 spaces were the maximum, now larger can be purchased, a 40-42 space is still a decent size.


I call Eaton BR, "Zinsco II" because it shares Zinsco heritage, the interiors are Challenger (Zinsco's successor) design, and is aimed at the same market that Zinsco was popular in.

 

[manoweb]

Yeah I'm looking at Siemens PL series (I used to live in Germany after all ) and the problem is - they seem to be very difficult to acquire, the Home Depot has them unavailable, other sellers have sketchy websites with outrageous prices ??? Is there a known shortage in electrical panels going on right now?

 

[beemerphile]

Wouldn't the simplest end-game route be to mount an additional service disconnect alongside the existing one at the meter and run the feed to a distribution panel in the new detached structure? (Ref. NEC 230.71) It seems like anything done to the existing panel, though it may be worthwhile, is optional to this project. Whether the meter base and service need to be upgraded or not would depend on what is there. If the service is needed in the old building until the new building is finished, the second DP could be located first in the current building and then relocated under a second permit when it is time to move over.

 

[u2slow]

Since you have the main breaker outside, you'll have an easy time doing things safely.

I would put in a pad-mounted splitter box ahead of the existing panel. Then tap off to a new panel of your choice. You can add extra loads there, and swap circuits over at your leisure. Eventually take out the FPE panel.

 

[nadogail]

I would consider powering my construction project and welder with my Generator, and then updating the house panel to match what went into the new construction.

The existing house panel might work as a sub panel fed from the new construction.