Adding Load on an Existing Transformer

[Electriman]

Greetings,

I was wondering if NEC has any section on when we are adding loads to an existing transformer. I have readings of the transformer (500kVA) and I know the demand load in the worst case scenario which is less than the connected loads. Now I would like to add some new loads and I was wondering what is the maximum load that NEC allows me to add in this case. For instance, if my measured load is 200 KVA, does NEC allow me to add 300 KVA?

Thank you in advance.

 

[Rock86]

How do you feel about using 220.87?

 

[augie47]

I can't say that the Code addresses it directly other than protecting the transformer from overloads per Art 450 and doing calculation per Art 220..

 

[electrofelon]

For instance, if my measured load is 200 KVA, does NEC allow me to add 300 KVA?

Thank you in advance.

Sure why not? Now that is assuming the 200 is measured correctly and the other equipment and conductors are rated for the 500kva