formula ques?

[wireman1]

to find the amps of a 5 hp motor rated at 480 volts i lost my book with all my formulas.give example how to find amps for above ques. 2nd ques? article 300 .6 (a) requires a listed compound for coating field cut threads on imc and rigid conduit in the field . as far as i know the only one out there is kopor shield made by thomas and betts that is listed for this application . is there any new ones listed ?

 

[nakulak]

your profile says you are an insepector. what's that ?

 

[chris kennedy]

your profile says you are an insepector. what's that ?

They come to your jobs to make sure they are code compliant.

 

[mpd]

They come to your jobs to make sure they are code compliant.

thats an inspector

 

[chris kennedy]

Time to call in the English Majors from ET.

 

[480sparky]

Time to call in the English Majors from ET.

Don't you mean the Spelling Gestapo and the Grammer Nazis? :grin:

 

[radiopet]

3-Phase with known HP:

__HP x 746______
1.73 x E x Eff x pf

1-phase with known HP:

__HP x 746___
E x Eff x pf

E = Volts/Eff = Efficiency/pf = Power Factor

Have Fun !

 

[don_resqcapt19]

For code work there are only two currents for motors that apply. The motor circuit conductors, and the circuit short circuit and ground fault protection are based on Tables 430.248 through 430.250. There are no formulas involved. The other motor current for code work is the motor full load current as found on the motor nameplate which is used to size the motor overload protection.
As far as the code required corrosion protection for field cut conduit threads, the code rule does not require the use of a "listed" product. It only requires the use of an "approved" product...that is one that is acceptable to the AHJ. I believe you are correct that the only listed product is the T&B KoprShield, but there are similar products that can be approved for the purpose.