wire size

[Duffin]

25kw 3 step heat at 69.39amps asked for #3 wire. Is this right?

 

[augie47]

lots of "depends"
25 kw @ 208 3 phase evenly distributed would be 69.4 amps

422.10 would require an ampacity of 86.8 amps in most cases

From there, it's a case of type wire, etc. #3 THHN normal conditions, yes
#3 NM, no #3 SE Interior wiring '05 Code yes '08 Code no

 

[infinity]

Does the unit specify an MCA?

 

[Duffin]

Can you show me the math so I can use it in the future?

 

[augie47]

25,000 / 208*1.732 for 3 phase 208

 

[Duffin]

I do not know what that means. All I have is the information I stated, 25kw
at 69.39A. Says #3 wire is needed and would like to know how they came up with the wire size. What size breaker would you use?

 

[Duffin]

Mca? What is that?

 

[480sparky]

Mca? What is that?

Minimum circuit ampacity.

 

[Duffin]

All the information I have I stated. Can you show me code # for my boss?

 

[infinity]

You never stated the voltage.

 

[augie47]

What type of equipment are we dealing with ? (air handler with unit heat, duct heater, heat pump, package air unit, water heater)