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A #8 copper conductor with an insulation factor of 60 degrees C is rated at 40 amps. For a built in safety factor, a #8 conductor with an insulation factor of 75 or 90 degrees C has a rating of 45 amps.

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14y ago
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16y ago

#10 is ok in some states, the nec says #8.

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11y ago

In most conditions you can use 8 AWG, but if there are any questions, contact a qualified electrician or your local building inspector.

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11y ago

AWG # 8 copper.

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11y ago

#8

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Q: What size cable for a 40 amp breaker?
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Can a 40 amp breaker not a 4 amp breaker be used to replace a 35 amp breaker for ac unit?

Depends on the size of the wire going to the A/C. If the wire is AWG #10 you cannot install a 40 amp breaker. If the wire is AWG #8 you can.


What size wire cable and fuse for a 9.8KW shower?

7.2kW shower = 32 Amp fuse = 6 mm2 cable size7.5kW shower = 40 Amp fuse = 10 mm2 cable size8.5kW shower = 40 Amp fuse = 10 mm2 cable size9.5kW shower = 40/45 Amp fuse = 10 mm2 cable size10.5kW shower = 45 Amp fuse = 16mm2 cable size


What are the standard size circuit breaker amperages?

In North America the standard sizes for breakers are 15, 20, 30, and 40 amps. The 15 amp size breaker is used in general circuit wiring. The 20 amp size breaker is used for dedicated appliance receptacles, hot water tank and baseboard heating. The 30 amp size breaker is used for a clothes dryer. The 40 amp size breaker is used for the electric range.


What size wire for 28 amps?

Minimum size is 10 gauge with a 30 amp breaker. To be safe I would install an 8 gauge with a 40 amp breaker.


Can an electric range be powered from the same circuit as an electric dyer?

No. The two appliances usually have dedicated circuits. The range will have a two pole 40 amp breaker and be fed with a 3-C #8 copper cable. The dryer will have a 30 amp two pole breaker and be fed with a 3-C # 10 copper cable. As you can see by powering a 40 amp device from a 30 amp breaker, full operation of the range will trip the 30 amp breaker.


What size wire and breaker do you need for a 5000 watt garage heater?

Look on the heater and see what amps it is pulling. That will determine the wire size and breaker size. It must be on a dedicated circuit. 15 amps = AWG # 14 wire with 15 amp breaker 20 amps = AWG # 12 wire with 20 amp breaker 30 amps = AWG # 10 wire with 30 amp breaker 40 amps = AWG # 8 wire with 40 amp breaker


What size breaker do you need for a 40 gallon electric water heater?

Usually 30 amp


What is breaker size for 240 volt 9 KW?

The formula you are looking for is I = W/E.


Can you use 40 amp breaker for your lights and plug ins?

If you are referring to house wiring then the answer is no. A breaker protects the wire size that is connected to the breaker. In home wiring most homes are wired with a #14 wire which is rated at 15 amps. That is why the wire is protected by a 15 amp breaker. The correct wire size to connect to a 40 amp breaker is a #8. This size wire is too large to connect to receptacles an light fixture terminals.


Is it ok to exchange a 20 amp breaker with a 40 amp breaker?

No. The 20 amp breaker is probably protecting a #12 wire. Connecting a 40 amp breaker to the 20 amp #12 wire would seriously overload the #12 wire. This means that if the load increased to a full 40 amps the insulation on the smaller size wire would most likely melt off and the wire could short out.


Will your spa work with a 40 amp breaker even if it says 50 amp on the plate?

No, because if you switch a 50-amp load on, it will blow a 40-amp circuit breaker if the load exceeds 40 amps, which is likely.


What type of appliance would be use a two pole 50 amp breaker?

In North America this size breaker could be used on a welding machine. A range in the home would use a 40 amp two pole breaker.