fuse proximity to control transformer 2

[QGeek]

I am redoing a cabinet layout. We are using a different control transformer that is larger, and so the fuse holder that was formerly mounted on top of the transformer is being replaced by two DIN-rail mounted fuse holders (2P primary + 1P secondary). I am wondering what the proximity constraints are for the new fuse holders. Don't they need to be very close to the transformer?

1000VA transformer 460/230 VAC. Open type.

 

[waross]

I believe that the limit on conductor length is three feet. (Each conductor.)

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[QGeek]

This is great, thanks. I will be well within bounds. I appreciate the assurance.

 

[waross]

A disclaimer:
I work under the code governing field installations. I just checked and the length is 3 Meters, not 3 feet. However there are limits as to conductor size depending on a number of conditions.
Panel work may fall under different codes and approvals. The rules as to minimum conductor size may be more lenient.
Someone with panel design experience may have more applicable information.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[ScottyUK]

Knowing which nation's regulations are in force has some relevance to the answer to the question.

 

[LionelHutz]

A star for giving the wrong length for the wrong section of wire? The 3'/3m length is the CEC/NEC tap length which is the length of the smaller conductor between the main incoming or main power wires and the fuses, not the fuses to the transformer.

Assuming you properly size the wire, why would there be a limit on the length of wire between the fuses and the transformer? The fuses protect these wire no matter how long they are.

As for the tap length, I would keep the wires feeding the fuses short, but I can't find any maximum length for these conductors in the UL508A - Industrial Control Panel standard. Possibly because it's assumed you won't make a control panel large enough to exceed the 3m length in the electrical code.

 

[waross]

I assumed 2 wires from the disconnect to the fuses, 3 meters max. No limit for the wires from the fuses to the transformer. The wires from the transformer to the secondary fuse, may be protected by the primary fuses, otherwise 3 meters or more depending on other factors. Wires past the secondary fuses, no limit on length.
And assuming properly sized fuses. lps for checking UL508A for the OP. More deserved than the other one.
Thanks Lionel.

Bill
--------------------
"Why not the best?"
Jimmy Carter