Ev charger wire and ocpd sizing

[don_resqcapt19]

What you said is correct to me.

The white page from UL is here:

https://code-authorities.ul.com/wp-content/uploads/2014/09/UL-White-Book.pdf

Molded Case Circuit Breaker - Marking and Application Guide | UL Solutions Code Authorities

UL Marking and Application Guide for molded case circuit breakers and related hardware.

code-authorities.ul.com

Eaton's guide:

https://www.eaton.com/content/dam/eaton/products/electrical-circuit-protection/fuses/solution-center/bus-ele-tech-lib-conductor-ampacities.pdf

UL's guide is not a fun or easy read. It also disagrees with the NEC where it says the 75°C rating used on wires of 1/0 or larger and the NEC says #1 or larger.

I had a disagreement a little while back with another engineer about it. We came to the following consensus (and this might extend past what the OP posted).

In a simple system, you have the panelboard connected to the breaker, connected to the wire, connected to a termination connected to the load.

Or there is another termination in the panelboard when there is no breaker.

In any case, everything must be labeled 75°C. The enclosure, the breaker, the wire, the terminations, etc. And the terminations must also be labeled with the wire size. If it doesn't include the wire size then the lower temperature shall be used.

Nothing is rated 90°C except for wire and terminations. Panelboards, breakers, etc. are not tested by UL at anything higher than 75°C. Crazy enough that they don't. To me it sounds like a simple win on the manufacturer to get that product stamp on high ampacity switchgear.

No equipment is rated for free air. As soon as a conductor enters a switchgear it is no longer free air rated. As soon as the conductor touches a breaker, it is no longer free air rated. Even if the whole assembly is exposed in free air. And debatably, and this is still something I haven't been able to confirm, but terminations on bus duct are not allowed to use the free air rating because the component parts enter enclosed switchgear.

Where does that part come from? However it really doesn't matter as all terminations are required to be marked with the conductor size.

 

[tortuga]

Per UL 1660 Section 6.1.3(d), LFNC may have an 80C, 90C, or 105C dry location rating and is to be so marked. Per Section 6.1.3(g), the wet location rating is always 60C, and marking that is therefore optional.

IIRC, LFMC is similar.

Cheers, Wayne

Good reminder thank you, its not as clear in the code as 334.80 & 340.80.
So if OP were to use liquidtight, NM or UF into the charger EVSE with a 50A nameplate #4 CU would be required for the 70A
MC, SER, EMT, TC, or PVC #6 CU would be OK on the 70A.

EDIT: I gotta stop calling it a charger as its not an appliance.

 

[Elect117]

Where does that part come from? However it really doesn't matter as all terminations are required to be marked with the conductor size.

https://code-authorities.ul.com/wp-content/uploads/2014/09/UL-White-Book.pdf

From UL AALZ, in the previously quoted section.

"If the termination provisions on equipment are based on the use of other conductors, the equipment is either marked with both the size and temperature rating of the conductors to be used or with only the temperature rating of the conductors to be used. If the equipment is only marked for use with conductors having a higher (75 or 90°C) temperature rating (wire size not specified), the 60°C ampacities (for circuits rated 100 A or less) and 75°C ampacities (for circuits rated over 100 A) should be used to determine wire size. "

How I read it:
If the equipment is only marked for use with conductors having a higher temperature rating (wire size not specified), the 60°C ampacities (for circuits rated 100A or less) should be used to determine the wire size.

 

[Elect117]

OK, this excerpt from UL AALZ Guide Info is under the section "Appliance and Utilization Equipment Terminations." So if it is to be believed, it would not apply to breakers, devices, or EVSEs, just to appliances and utilization equipment.

Cheers, Wayne

Actually, I'm not finding any support for this idea in the UL category info or in the application guide https://code-authorities.ul.com/molded-case-circuit-breaker-marking-and-application-guide/

I think if the breaker is marked just "75C" you must use at least 75C rated insulation, but get to use the 75C ampacity.

Cheers, Wayne

I think you are right.

I still don't get why the terminations would need to be marked both. Unless it is a typo on the document.

And why they say "A 75°C conductor temperature marking on a circuit breaker or switch normally intended for wire sizes 14-1 AWG does not in itself indicate that 75°C insulated wire can be used unless 1) the circuit breaker or switch is used by itself, such as in a separate enclosure, or 2) the equipment in which the circuit breaker or switch is installed is also so marked.".

I get different products have different testing standards. Almost every individual standard (cable, panelboard, breakers of different types, etc.) say that if it is marked 75°C you use the 75°C rating. But in AALZ they throw in these loops with it. Like extra tid-bits or steps that also need to be considered.