electric heat

[wire monk]

How do you figure the wire size on a 10 kw single phase 240 volt electric furnace??

 

[480sparky]

Ohms' Law, then Table 310.16.

Or cheat, and look at the nameplate.

 

[HEYDOG]

You also need to look at 424.3(b) and 424.11

 

[LarryFine]

How do you figure the wire size on a 10 kw single phase 240 volt electric furnace??

By the Min Ckt Ampacity.

 

[Dennis Alwon]

How do you figure the wire size on a 10 kw single phase 240 volt electric furnace??

The nameplate will tell you what you need to know.

10000/240= 42 amps
42 * 1.25 = 52.5

Now use table 310.16

Let me warn you that most units that are 10 kw do not have 10kw of heat. Many have 9.6 kw. You must check the nameplate because some of these units I have seen actually requires a min. ampacity of 56 amps which means and #4 copper if you use NM or seu cable.

 

[suemarkp]

Or the heat fits under 55 amps, but then the dang blower motor pushes you over. So its #6 THHN in a raceway, or #4 NM cable.