Shopsmith Forums

I thought I would move the electrical discussion from the other post here for later reference,,maybe some day some one will have a issue .

On the other post I mentioned a breaker would blow at or above 80% of its UL rating,,

if you research the ratings on breakers,they are rated by continuous or noncontinuous duty , 80% or 100% depending on the duty status of the circuit.

Not sure how many continuous duty status circuits are installed in a residential situation ,, however,,,, It hand't dawned to me we have folks here with commercial applications.

Here is a link to what I have found that should clear it up.

http://blog.schneider-electric.com/data ... -breakers/

I read through your link, but I'm not sure it really cleared things up for me. The good news is that most of this doesn't matter to us. If we use the circuits as intended and don't overload them, we likely won't have any breaker tripping problems.
I don't believe I have ever had a false trip on a breaker. Any time one tripped, it was because it was overloaded or there was a short circuit, and in those cases, it needed to trip.
I did learn something interesting with my air compressors in my garage. In cold weather my small 120v compressor would sometimes trip its 20a breaker when trying to start cold. My solution was to replace the #12 wire with #10 wire and keep the original 20a breaker. The motor spins up fast now and never trips the breaker.
When I added a large 240v compressor, I did the same thing. It needed a 30a circuit so I used #8 wire instead of the recommended #10 wire and used a 30a breaker. The motor spins up faster and has never tripped the breaker.
I see people recommending keeping the #10 wire and putting in a 40a or 50a breaker to avoid trips. That scares me to do it that way.
Smaller wire means slower starts and shorter motor life. Faster starts result in better motor life.

You should never replace a breaker with a higher amperage breaker if the breaker is tripping. Breaker size is mandated based on the wire gauge attached to the breaker. You might as well not have a breaker if you just bump the amp size up. You are guaranteeing an electrical fire for someone if you just upsize the breaker without also upsizing the attached wire from end to end.

Hobbyman2 wrote:I thought I would move the electrical discussion from the other post here for later reference,,maybe some day some one will have a issue .

On the other post I mentioned a breaker would blow at or above 80% of its UL rating,,

if you research the ratings on breakers,they are rated by continuous or noncontinuous duty , 80% or 100% depending on the duty status of the circuit.

Not sure how many continuous duty status circuits are installed in a residential situation ,, however,,,, It hand't dawned to me we have folks here with commercial applications.

Here is a link to what I have found that should clear it up.

http://blog.schneider-electric.com/data ... -breakers/

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I know what you mean when you say,,,,,, most wont need to worry,,,,,,,as long as the wiring is done right the first time,.

I also know it gets pretty cold n Bismark and folks do things in the north they wouldnt need to do in the southern states , like superpop said though ,,,,

There is supposed to be a ul rating one every piece of eq,, or use to be so ,, yo should stay with the ratings or a failure is around the corner,, I knew a fella that had a old 60 amp fuse box and had pennies behind several fuse, said they were that way for years and he would not up grade for nothing,, a few years later his house burnt do to electrical failure..

Years ago I was discussing electrical issues with a fella in Austrailia ,, every thing there is 50 hz if I recall and 220 v including lighting ,,,

I am not telling every one what to do,,,, not my intentions ,,,, just there could be more things to inspect then just the eq in a epic failure .

until you can rule out the cause it could happen over and over.

one more thing is ,,,,, some areas are 110 volt and some are 120 volt ,I was working in WV once and the voltage was 108 volt , stuff worked ,, motors would start a little slower and the lights would some times dim ...most equipment should run on either, from what I seen in the field ,, it will work on a 120 volt a little more efficient.

#12 wire on a 20A circuit is not 'recommended', it is a 'minimum satisfactory'.

Long wire runs require larger wire. Same for current demand surge devices(induction motors starting).

some gfi stuff wont except 10 awg wire.