In article .com, "volts500" wrote:
Doug Miller wrote:
In article . com, "Russ"
wrote:
After a new electric range was installed the circuit breaker started to
pop every now and then when everything was turned on (oven+all
burners). This indicated to me that the range was drawing a load that
was right at the upper limit of the 50 amp circuit breaker rating.
Checked the data plate on the range which reads 240V. & 54.2 amps. So,
when the range is at peak load it apparently can draw 4.2 amps over
the breaker capacity. The wiring is Aluminum 6 guage (6 Al on the
sheath),. Can I safely go to the next size breaker (60 amp) to
accomodate the additional 4-5 amps???

Probably NOT, but it depends on the temperature rating of the insulation on
the conductors; this should also be indicated on the cable sheath -- if it is
not indicated, assume it's 60 degrees C.

With a 90-degree rating, yes, you can go up to 60 amps.

This is incorrect, if not a fire hazard. The temperature ratings of
the lugs on the breaker and the range must be rated for 90 degrees C.
I can assure you that they are NOT. The 90 degree C rating is used for
derating conductors, such as for ambient temperature or more than three
conductors in a conduit, etc. If one uses 90 degree C wire at the full
rating, then one must also use 90 degree C lugs for terminating. Good
luck finding a residential breaker rated for 90 degrees C.

I stand corrected. Thank you.

If the rating is 75 degrees, you're limited to the 50 amps you're already at.

This will be true only if the terminals of the breaker and the range
are rated for 75 degrees C. Some residential breakers are rated for 75
degrees C, some are _not_.

Ditto.

And if it's only 60 degrees, you shouldn't have even a 50 amp breaker -- it's
limited to 40 amps by Code.

IIRC, a #4 copper THHN is rated for 70 amps at 60 degrees C. If using
Romex, since Romex cannot be used over the 60 degree C rating, that
would work with a 60 amp breaker with 60 or 75 degree C terminals.

Yep.

Bottom line, the OP needs to install a new circuit.

Sounds like it.

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.