I'm adding a 40A breaker to the existing panel in my condo to charge an EV (Electric vehicle). I called the city and they said that as long as I have space for the breaker that would be ok. I do have the space but I have to move a 15A breaker to the other side of the panel (Panel is challenger SL12(8-16)CGN) where the connection tab is is the opposite side. Then get the 40A and a 15A breaker. These old breakers are very expensive, $25 for the 15A and $50 for the 40A, maybe because they have the connection in the corners and not the center. The place was built in 1986 (Southern California). I can buy newer breakers and a new panel for about $100 (Square D homeline panel and breakers).

Would I need to use AFCI breaker (new NEC code) if I change the panel? That would change the price too much to do it.


Panel label Breaker Panel

  • Are they stab lock breakers? If so I would be looking to be updating the panel for safety reasons. The breaker design is prone to failure and 2x for double pole. The only work I will do on stab lock type breakers is to remove and replace the panel.
    – Ed Beal
    Aug 14, 2018 at 18:45
  • 1
    IIRC, AFCI breakers are required when changes are made to the wiring not the panel. Here's a better answer: diy.stackexchange.com/questions/140959/…
    – Hari
    Aug 14, 2018 at 19:37
  • Crikey, for that kind of money I would slap a Siemens 30 or 42 space panel right next to it, double-lug the panel so both are mains, and install my own $8 breakers. About once a week migrate a circuit from the Challenger to the Siemens. Whenever. When all the circuits are gone, yank out the Challenger guts leaving just a lug splice. Aug 14, 2018 at 19:40
  • Can you post a clear photo of the labeling on the existing panel? Aug 14, 2018 at 22:29
  • Also, what size is your service, how many square feet is your condo, and do you have other major loads running off of this panel? (Look for double pole breakers, or breakers >20A) Aug 14, 2018 at 22:30

3 Answers 3


Your problem isn't the panel...

The panel you have is adequate for what you're doing -- swapping the circuit that makes up the bottom half of #9 to the slot below #6 (if worse comes to worse, just drop a BR115 in there as BR breakers are cross-listed to fit Challenger panels) will free up enough room for a two-pole breaker in the two bottom right slots, although this panel does not have much wiggle room indeed.

...but the size of your feeder

However, your condo's feeder is too small for the additional load posed by the electric car charger. Working through the article 220 procedure, we get 3000VA of lighting load (split across two circuits here), and then add to that a pretty healthy chunk of small appliance load (1500VA per small appliance branch circuit * 6 = 9000VA total) factored by the 35% demand factor for loads over 3000VA. Adding in the 18A air conditioner, we get almost 43A of load, before we add the car charger at 32A continuous, which puts us at 75A, well over the size of your 60A feed, and a good reason to have the feeder to your condo upgraded to 100A or 125A to go along with having a new panel installed.

As to until that point? You might be able to get away with running the car charger at night; however, I would keep an eye on your main breaker (which will be off outside your unit) -- if it trips, that's a sure-fire sign you'll need a service upgrade.

If you do put a new panel in...

If you do decide to have the panel upgraded, that 11" wide stud bay is quite the constraint; however, there are better options than putting in a 10 space panel and living with the space shortage, though, as you can take two or three of those narrow panels and daisy-chain them together using sub-feed lug blocks to extend the feeder down through two or three panel interiors and conduit nipples to connect the enclosures together. This lets you have oh, about 24 to 30 spaces at the cost of taking up most of that stud bay with panels and nipples, and needing to do some gymnastics to route wires out from the lower panels, but it may be worthwhile given the space constraints you are up against.

You may also be able to gain a couple of spaces by removing the main breakers from the BR1020B100F11 panels you're using -- they use a backfed BR breaker as their main, so if they have main lugs that are sitting fallow, I'd pull the main breaker out in that case and use the main lugs instead, in addition to the subfeed lug trick described above. (That way, you probably could get 30 spaces' worth of panel in your 11" wide space.)

  • Yeah, I wonder why they installed such a low rated service entrance cable but I guess back in those days they didn't see any need for more. Replacing it is out of the question though. I'll be replacing the panel with a 10 space one. I'm very limited because of the size and location of the current panel (11in (W) by 15in (H)). There are studs that force the 11in size and that small wall is 18in wide. Thanks for the info on the AFCI.
    – Rodo
    Aug 19, 2018 at 15:23
  • @Rodo -- let me suggest to you some better options for a replacement panel setup then Aug 19, 2018 at 15:29
  • Suggest away...the height can be bigger than 15in. I see/feel no fire blocks. The 11in width is a must. So far I'm going with Eaton BR1020B100F11, which is a 100A panel compared to 125A that I have now but with a 60A main breaker and a 75A cable seems ok to me. Thanks.
    – Rodo
    Aug 19, 2018 at 17:43

I finally called the city and talked to an inspector. My city, Diamond Bar (California) said that I did not need to have AFCIs. The GFCIs were already in the outlets in the right locations so a new panel with regular breakers was ok.


Panel is challenger


These are horribly dangerous and this needs replaced ASAP!



  • 4
    Not all challengers are stab-lock. It looks like this panel accepts Type C breakers which can be replaced with (UL classified) Eaton type BR breakers. See ThreePhase's answer for more details here: diy.stackexchange.com/questions/91429/…
    – Nate S.
    May 6, 2019 at 20:18
  • 2
    @NateStrickland -- it's better than UL Classified (which is sometimes considered debatable), even: Type BR breakers are fully UL cross-listed and cross-labeled as Type C (as the post you linked details). May 7, 2019 at 0:51
  • 1
    Note that any issues that are present with Challenger are with the uncertain heritage of the breakers; the panelboard (loadcenter interior) is not an issue, as it's a BR clone (to the point where Type BR breakers are cross-listed/cross-labeled as Type C, even!) May 7, 2019 at 0:53

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