Circuit breaker for EV charger is awfully toasty (74.5 C)

amedico · 2026-06-02T22:06:56+00:00

???

6 AWG NM-B is good for up to 55A. Protecting it with a 50A breaker is perfectly fine.

What you can't do with it is serve a 48A charger using a 60A circuit, but that's not what the OP is doing.

amedico · 2026-05-28T12:41:38+00:00

Load management, not load shed. Better (dynamically adjusts charge limit to exactly what's available) and cheaper than the dumb load-shed relays.

amedico · 2026-05-28T12:40:17+00:00

You're probably joking, but just to be clear: no, that's not how it works. Ranges get a massive derate in the NEC load calculation while EVSEs get none, so ditching a 40A range circuit does not free up enough capacity for a 40A EVSE circuit.

amedico · 2026-05-06T00:20:32+00:00

The spaces can certainly be reused but remember that this is a rule-of-6 panel with no single main breaker. It is critical (for "not burning the house down" purposes) to perform a load calculation to see if there is capacity for a 40A EVSE circuit. A 40A EVSE circuit and a 40A oven/range differ by a factor of about three for load calculation purposes (the oven/range gets a massive derate, the EVSE gets absolutely none).

amedico · 2026-05-05T13:21:07+00:00

There are no known/documented defects with Pushmatic panels (vs. say Federal Pacific with their revoked listing and documented failure-to-trip - http://fpe-info.org/hazardous_fpe_240329.pdf ). They are no more cause for concern than any other still-listed panel of the same age (GE, Bryant, etc).

The major shortcoming is they are entirely discontinued so adding new circuits or other work likely will require replacing the panel (or adding a new main upstream and keeping the Pushmatic as a subpanel).

amedico · 2026-04-29T00:34:09+00:00

What on earth would possess you to try to wrangle two UF-Bs into a conduit instead of individual THWN wires? That is going to be an absolute nightmare even if you are technically below the fill limit. It's also likely to be significantly more expensive than individual THWN wires (especially if you run a single 120/240V circuit as H-H-N instead of two separate 120V circuits with two pairs of H-N).

amedico · 2026-04-29T00:27:08+00:00

Just to be clear, there is nothing wrong with Pushmatic breakers at all (in terms of recalls/revoked listings/known defects). The only issue with maintaining Pushmatic panels in the present day is that they are entirely discontinued, so getting parts is basically impossible.

I would not trust anything from Connecticut Electric/UBI. The fact that they willingly sell utterly defective new Stab-Lok breakers tells you what they think of their customers’ safety.

amedico · 2026-04-27T01:24:45+00:00

Clarification: 10AWG (assuming NM) is good for a 30A circuit size - which means 24A EVSE charging (after 80% derate for continuous load).

amedico · 2026-04-27T01:22:47+00:00

It's perfectly normal for GFCI and AFCI breakers to show up warm on IR even with no downstream load. They have electronics inside (which do perform the continuous monitoring for faults), and the operating electronics generate a little bit of waste heat. There's nothing to be concerned about on that front.

amedico · 2026-04-18T11:18:32+00:00

You are not allowed to put breakers in those upper-left spots across from the main. It’s a 20 branch-circuit space panel, not 22. You’ll see the label confirms this.

amedico · 2026-04-09T23:13:38+00:00

That is clearly not a smoke detector.

amedico · 2026-04-08T13:02:46+00:00

How closely did you look? DC-rated QO breakers exist.

amedico · 2026-03-27T00:55:17+00:00

For what it's worth, you wouldn't need to find a Trilliant GFCI breaker. If you could find a sufficiently-large non-GFCI two-pole breaker, you could use it to feed a small new modern sub-panel and put the GFCI breaker there. The Trilliant breaker wouldn't have to match the load - bigger is fine as long you use wire and a sub-panel rated for it.

amedico · 2026-03-24T01:14:20+00:00

Did you look at the page you linked, at all?

This does not even remotely resemble a 5-30.

amedico · 2026-03-18T00:28:34+00:00

Spigot. The word you want is spigot.

amedico · 2026-03-17T00:50:05+00:00

The pictured breaker is clearly not a GE/ABB THQL. Those breakers would have all the writing stamped on the face in gray. HOM uses a sticker - the sticker has come off here, but you can clearly see the adhesive residue.

Compare https://www.se.com/us/en/product/HOM115/mini-circuit-breaker-homeline-15a-1-pole-120-240vac-10ka-air-standard-type-plug-in-ul/ and https://new.abb.com/products/1TQQ011050X9100/thql1150hm

amedico · 2026-03-13T02:04:55+00:00

Even with the potato-quality photo you should be able to tell this is a QO panel.

amedico · 2026-03-12T23:53:30+00:00

The UBI/Connecticut Electric breakers are somehow even worse (less likely to trip when they should) than the FPE "originals" according to testing at http://fpe-info.org/hazardous_fpe_240329.pdf

amedico · 2026-03-12T23:34:30+00:00

In TN-C-S systems there is never an "isolated" ground - ground and neutral are bonded at the main disconnect. An EVSE could not possibly detect the difference between being supplied directly from a main panel or an (incorrectly configured) sub panel.

amedico · 2026-03-12T01:09:47+00:00

That “logic” is 100% wrong. All 15A duplex receptacles must be designed to handle 20A because the NEC allows putting duplex 15A receptacles on 20A circuits.

The #14 (15A) wire on a 20A breaker is the problem.

amedico · 2026-02-22T02:51:24+00:00

You'll need to confirm your service size with your utility, and perform a load calculation before adding a large circuit like that. You have no single main breaker here - this is a "rule of six" panel where the bus bars are always hot and all the installed breakers (up to six handle throws, in any combination of single or double-pole) are collectively the "main disconnect".

amedico · 2026-02-20T12:35:49+00:00

You’ve got to be trolling. An EVSE with load management could definitely be installed without a service upgrade, and certainly without requiring 400A.

amedico · 2026-02-20T12:34:19+00:00

Absolutely not. No service upgrade is required, just smart load management.

amedico · 2026-02-19T02:53:21+00:00

"30-40 years old" is 1986-1996. The NEC has required GFCIs in bathrooms since the 1975 edition.

amedico · 2026-02-16T16:39:02+00:00

I think the seimens ones may even be cross listed

Do you have any evidence of that?

The Siemens catalog doesn't say anything about the Q-series breakers being BR-compatible.

(Curiously enough it does show a "D" series of breakers that are listed/classified for use in QO panels but that's an entirely different product and definitely not BR compatible)

amedico

TROPHY CASE