Indoor Electric Cable Types

I am about to install a portable generator hookup and since it is reeeally important to properly size my cable between the inlet box and my main load center, I thought I share what I found out.

Although I use the term “Romex” (brand owned by Southwire) you can certainly use other brand with same specs (i.e. Cirtex made by CirroWire).

Image	# of Conductors	Cable Type	AWG Size	Ground	Stranding	Ampacity
	Two, Copper	NM-B 14/2	14/2	14 solid	Solid	15 amps @ 75 celsius
	Three, copper	NM-B 14/3	14/3	14 solid	Solid	15 amps @ 75 celsius
	Two, Copper	NM-B 12/2	12/2	12 solid	Solid	20 amps @ 75 celsius
	Three, copper	NM-B 12/3	12/3	12 solid	Solid	20 amps @ 75 celsius
	Two, Copper	NM-B 10/2	10/2	10 solid	Solid	30 amps @ 75 celsius
	Three, copper	NM-B 10/3	10/3	10 solid	Solid	30 amps @ 75 celsius
	Three, copper	NM-B 8/3	8/3	10 solid	7 strands	40 amps @ 75 celsius
	Three, copper	NM-B 6/3	6/3	10 solid	7 strands	55 amps @ 75 celsius
	Three, copper	NM-B 4/3	4/3	8 strands	7 strands	70 amps @ 75 celsius

Quick Size and AMP Ratings (NM, TW & UF WIRE)

• 14 AWG – 15 AMPS
• 12 AWG – 20 AMPS
• 10 AWG – 30 AMPS
• 8 AWG – 40 AMPS
• 6 AWG – 65 AMPS

Quick Size and AMP Ratings (SERVICE CABLE)

• 8 AWG – 50 AMPS
• 6 AWG – 65 AMPS
• 4 AWG – 100 AMPS
• 2 AWG – 125 AMPS
• 1 AWG – 150 AMPS

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Thanks and good luck with your DIY project!

REFERENCES

• What does Romex® Mean?

Wire Size and Amp Ratings