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∙ 8y agoA #3 copper conductor with an insulation factor of 90 degrees C is rated at 115 amps. Even though the panel is rated at a higher amperage it is the main breaker that governs the wire size.
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∙ 8y agoYes you do. The detached garage will either be fed with a single circuit or a sub panel. The wire feeding the garage will need to be protected and that is the purpose of the breaker (disconnect). The breaker size will be determined by the size of the wire that is used on this circuit.
You can reduce the breaker size because that limits the current that can reach the main panel. There is no safety issue other than the significant danger in an unskilled person changing out a main breaker.
A 100-A sub-panel would be fed from a 100-A breaker.
You can. Using these size breakers in a 60 amp sub panel might be pushing the limit for breaking the sub panels feeder breaker. The breaker feeding the sub panel will have to be no bigger than 60 amps because of the main bus bar capacity of the sub panel. It would be better to install a 100 amp sub panel and then there would be a bit of a buffer and you will have the ability to add additional small load circuits.
Look on the handle end of the main breaker. There should be a number there. That is the amperage of the main breaker. That is the size of your house service.
The biggest circuit breaker in any home is the main breaker located in your main breaker panel that is installed where your electrical service cable comes into your home.
50 amps
50 amps
Yes you do. The detached garage will either be fed with a single circuit or a sub panel. The wire feeding the garage will need to be protected and that is the purpose of the breaker (disconnect). The breaker size will be determined by the size of the wire that is used on this circuit.
The main breaker will have marking indicating size of electrical service, or if it is a fuse system....the fuses will have current ratings. If it is a subpanel, it might not have a main breaker. In this case you would have to look in the panel that the feed is coming from and find the size of the breaker that is feeding it. In either case you must look for the manufacturer's label that will have the maximum current the panel can handle, make sure the breaker feeding the panel doesn't exceed this rating.
In North America the smallest size breaker found in a home distribution panel is rated at 15 amps
Typically yes because that is what makes sense. However, the subpanel could have the same size breaker as long as the panel were rated for that amperage and the wire sizes were appropriate.
You can reduce the breaker size because that limits the current that can reach the main panel. There is no safety issue other than the significant danger in an unskilled person changing out a main breaker.
A 100-A sub-panel would be fed from a 100-A breaker.
There are two things to think about here. First of all a 200 amp breaker will not physically fit into a 100 amp panel. This is so designed because the panel buss is not designed to conduct 200 amps before the current is cut off. A 100 amp rating on the panel is the maximum amount of current that the manufacturer states, that can be handled safely. Second if the 200 amp breaker is in the main panel then everything downstream from that breaker has to be rated for 200 amp conductivity. The wire size will have to be 3/0 from the breaker to the first over current device in the sub panel which will be the sub panel's main breaker. The sub panel can not be a load center but will have to be a combination panel. I doubt that the 100 amp sub panel's main breaker lugs would be large enough to connect the 3/0 cable.
If it is a portable generator the breaker should be self contained within the generators panel. If the generator is a stationary standby unit a voltage has to be stated to calculate the conductor size and hence the breaker size to protect the conductor. Amps = Watts/Volts.
If you are talking about a breaker in a house panel then a 15 amp breaker would be used. It is the smallest amperage breaker that you will find in a house panel.