We are repurposing a room and in doing so we are upgrading the electrical. The electrician I use on most of my jobs is very good and has agreed to allow me to do the roughing and bill me only for his crew’s labor for making all the connections and terminations.
We discussed what materials I should use, but in my endless mental masturbations, I have come up with more questions. Instead of burdening him with all of them, I would like to solicit your advice so that I can be better equipped in my next discussion with him.
To start – all electric service to this one room will be removed (a wall sconce). We are running a new sub-panel from the main panel to the hall (3rd flr). This will service 4 wall outlets in the one room and 1 wall outlet in each of 3 other rooms. Total 7 outlets.
All outlets above will be for stereos, phone chargers, lamps, tv, computers.
There will be 2 new ceiling light fixtures in the one room.
I plan to install a split-system AC unit this summer so I would like to prep for that – 208/230v, 25amp.
Installing a stackable washer/ dryer (gas). (Add dedicated outlet).
Electrician recommended #8, 3-wire + ground to the sub-panel. The panel for a #8 wire is a 45 amp panel, but that panel a) doesn’t have enough spaces (4) and b) doesn’t have a door to cover the breakers. I found a 100amp panel that has 10 spaces for 20 circuits. Can I run a #8 wire to it and meet Code or do I have to run #2 wire?
100amp panel is an Eaton/ Cutler-Hammer BR1020B100FRVN.
Frankie
Replies
The only issue with a larger panel is whether the terminals are rated to clamp the smaller wire.
The 100a breaker is rated for #4-1/0 so the 8ga wire will not work. If you got the panel with a smaller breaker it would work.
If you ever are thinking of upgrading, why not just run the #2?
Yeah, that's basicaly what I was asking but was being a bit obtuse. What determines the proper wiring: the panel rating or the breaker rating? Didn't quite realise there would be a conflict in wire size and compatability with breaker clamp.
Ohwahtagooseiam.
Frankie
The panel rating is the maximum the rails will handle (also establishes the max main breaker size).
The breaker feeding the feeder circuit determines the minimum wire size (#8 is 50a). The breaker in the sub panel would only be a disconnect at that point.
In the case of a sub panel in a single building you really do not need a main breaker in that panel, it can be disconnected from the breaker feeding it so you can use a "main lug only" panel.
Compared to labor, wire is cheap so I would think about bumping this up to at least #4 (fed with a 80a or even 90a breaker) and you can use the original panel you found. At a certain point you find the most popular panels are much cheaper than one that is exactly what you need but not used very often.
Yeah, the #8 would be "adequate" but would not leave you with much "breathing room". It's adequate for the above-stated loads, but throw in 2-3 space heaters or some such and it would get tight.
If 50a is all you would ever need
BR816L125FDGP
may be a better option. That is a main lug panel, 14-1ga on the lugs and 8 slots (16 circuits with skinny breakers)
There is a technique that is sometimes used when a large panel is needed on a small feed: "Abandon" the main breaker and "backfeed" the panel through a regular 240V breaker. I've seen panels with a kit installed for this (bars to lock out the main and lock the "backfed" breaker into place, so it can't be removed), and one would presume that the kit is "approved".
If you are using the back fed breaker, why bother to get a main breaker panel, just get the MLO model.
Why not within a single family dwelling? You should know where it is being fed from even if you didn't label it (but I would)
A main in a sub panel is just a false sense of security since the breaker lugs are still hot.
Maybe if we had the canadian rules about barriers on the main lugs it might mean more.
The strange thing is he might find a 100a main breaker panel cheaper than an MLO. I know that was true when I bought mine.
The one on the top of this thread is main breaker panel but the 100a breaker needs a minimum of 4ga wire.
But the breaker lugs are at one end of the box and well-isolated from the rest of the panel. Not child-proof, but reasonable protection from a screwdriver slip. And I vaguely recall that the "kit" I mentioned had a shield for the new "main" breaker terminals.