Best Answer

A #1 copper conductor is rated at 140 amps with an insulation rating factor of 90 degrees C at 240 volt single phase, will give you a full 100 amps at 200 feet. #4 wire should give you 95 amps. Anything over 200 feet you will start loosing more amps.

Lvl 1

WHAT ABOUT # 2 THHN CU WIRE

More answers

This is a voltage drop question. A voltage value needs to be stated. Assuming that the 100 amp panel is a single phase 120/240 volt sub panel. A #1 copper conductor will limit the voltage drop to 3% or less when supplying 100 amps for 200 feet on a 240 volt system.

AWG #6 will work fine at 100 feet with only a 2% drop in voltage which is acceptable.

Lvl 1

2/0

Q: What size wire for a 100 amp sub panel 40 ft away?

Write your answer...

Submit

Still have questions?

Continue Learning about Electrical Engineering

i just left lowes an they told me to run 100 amp to my building i would need wire size 2-2-2-4 alumninum and run it in conduit the lowes around here does not sell copper wire that size

A #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.

A 100-A sub-panel would be fed from a 100-A breaker.

For a 100 Amp breaker panel it would be 2 AWG. For 150 Amps it would require 2/0 (2 ought) aluminum wire.

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.

Related questions

20Sqmm

To answer this question the voltage value and whether the system is three phase or single phase needs to be given.

i just left lowes an they told me to run 100 amp to my building i would need wire size 2-2-2-4 alumninum and run it in conduit the lowes around here does not sell copper wire that size

A #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.

For a 100 amp service panel, typically a #8 copper wire or a #6 aluminum wire is recommended for grounding purposes. It's important to follow local electrical codes and regulations when selecting the correct size of the ground wire. It's always a good idea to consult with a licensed electrician for specific guidance based on your individual circumstances.

The wire size in a meter stack is governed by the size of the first over current device.

Yes, but at every reduction in wire size there has to be a breaker sized to the smaller wire size. The wire size for 100 amp panels is recommended at #3 copper conductor. From the 200 amp feeder panel you will require a 100 amp two pole breaker for each of the two 100 amp services. Keep in mind that if you run the 100 amp services close to maximum this will take away the capacity of the 200 amp service for other branch circuits coming off of it. Also keep in mind that if the panels are located, not in the same building as the 200 amp service that the 100 amp panels will be treated as separate services and will have to be constructed like a 100 amp service. This includes ground rods. Also the bonding screw will have to be removed that connects the neutral buss to the panel enclosure.

#8 would be fine if you ground each panel separately to the ground rod

A 100-A sub-panel would be fed from a 100-A breaker.

For a 100 Amp breaker panel it would be 2 AWG. For 150 Amps it would require 2/0 (2 ought) aluminum wire.

To answer this question a voltage must be given.

This is a voltage drop question. A voltage must be stated to answer this question.