24V XFMR secondary OCP?

[jeremysterling]

I've looked in art 450 and art 240. I cannot find an exemption for secondary conductor OCP for door bell transformers.

The door bell conductors run typically is longer than 10 ft 240.21(C)(2)(1)a.(?)

Table 450.3(B) note 2. implies secondary conductor protection, therefore leading me back to Art. 240.

Can someone tell me a code reference to avoid installing an in-line fuse holder with a glass 250 VAC 1 amp fuse for doorbell wiring.

 

[Jim W in Tampa]

They do not need fuse because limited power. It is not a bad idea to have one as it might save damage. Was taught a smart lesson on 24 volt transformers on hvac, add inline fue and saves the transformer if anytthing goes wrong

 

[iwire]

Doorbell transformer are class 2 power supplies, no additional overcurrent protection needed, it is inherent.

 

[JohnJ0906]

Check article 725.

That is probably a Class 2 circuit.

 

[jeremysterling]

Thank you Jim, Bob and John, for your help.

I will read up on Art725 and look for a class 2 listing on the 24VAC XFMR.

Thanks again!