Fusing a Control Transformer

[Dale Hayes]

Stepdown voltage on a single phase 100VA control transformer is from a 380volt primary to a 220volt secondary.

I am fusing both wires on the 380volt primary side. Are the two wires connected to the 220volt secondary considered hot? Do both of the 220volt secondary connections need to be fused?

Also, If my secondary were 120volt I would use red for the fused L1 and white for the neutral. What is a standard color scheme for the wires on the 220volt secondary side?

 

[LarryFine]

I am fusing both wires on the 380volt primary side. Are the two wires connected to the 220volt secondary considered hot? Do both of the 220volt secondary connections need to be fused?

You will have what's called a separately-derived system, which would be 'floating'relative to the earth and all of its representatives. No secondary conductor would be 'hot' re: the earth unless you intentionally ground one via a bonding connection between that conductor and your grounding electrode system.

[Also, If my secondary were 120volt I would use red for the fused L1 and white for the neutral. What is a standard color scheme for the wires on the 220volt secondary side?

Let me ask you: Why would you have a 'neutral'? Which wire would be 'hot', and why? What determines which secondary conductor each would be?

Now, apply the same questions to your 220v secondary.

 

[mdshunk]

Are the two wires connected to the 220volt secondary considered hot?

Not after you ground one of them.