Secondary load of a transformer: length without overcurrent protection?

[O'donisR]

I have to install a transformer and the secondary load will be 100 feet underground but there will be 20 feet of the secondary load exposed in EMT before conduit enter to the underground slap. load terminate in a fuse.also the primary is protected bu a fuse.

more: Transformer will be installed inside the meter room 20 feet from an existing underground PVC conduit that i will use to run my wires to the load located 200 feet in an office. secondary will terminate in a main breaker panel.

I think the secondary cannot be more than 20 feet expose without protection, main disconnect shall be installed next to the transformer to protect the 20 feet expose conduit, and terminate the load in a main lug panel. please help. Thank you

 

[Smart $]

..main disconnect shall be installed next to the transformer to protect the 20 feet expose conduit...

They are not secondary conductors after the disconnect.

 

[O'donisR]

Here is an image for a better idea, from what I know secondary conductor can be any length if they are installed underground and terminated in a disconnect, but I'm worry about the 20 feet run that is not underground, please see the images the red line will be the expose conduit and the black line the underground. do i need a disconnect of the side load? exposed conduit will be installed 2 feet from ground. Thank you

 

[augie47]

I would be of the opinon that the installation would not be to Code without secondary over-current protection due to the 20 ft of interior EMT.

 

[O'donisR]

I would be of the opinon that the installation would not be to Code without secondary over-current protection due to the 20 ft of interior EMT.

can the 25' tap rule applies here? conductors terminated in a over current protection. Thank you

 

[Smart $]

I would be of the opinon that the installation would not be to Code without secondary over-current protection due to the 20 ft of interior EMT.

I agree.

FWIW, for my first reply, I misinterpreted the OP as saying the disconnect was on the secondary.

 

[O'donisR]

I don't know what todo with this installation, the transformer needs to be 20 feet from the existing underground conduit due to working space area restrictions , I would like that some one explain to me if I can apply the 25 feet tap rules here? or maybe if I place the transformer above gutter on the wall just right on top of the underground conduit? thank you

 

[jim dungar]

... I would like that some one explain to me if I can apply the 25 feet tap rules here?

The 25' tap rule requires a protective device at the 25' point.

 

[texie]

I don't know what todo with this installation, the transformer needs to be 20 feet from the existing underground conduit due to working space area restrictions , I would like that some one explain to me if I can apply the 25 feet tap rules here? or maybe if I place the transformer above gutter on the wall just right on top of the underground conduit? thank you

Can't you just make the panel at the far end MLO and install a breaker or fusible disconnect at the secondary of the transformer in the meter room? Am I missing something here?

 

[Smart $]

I don't know what todo with this installation, the transformer needs to be 20 feet from the existing underground conduit due to working space area restrictions , I would like that some one explain to me if I can apply the 25 feet tap rules here? or maybe if I place the transformer above gutter on the wall just right on top of the underground conduit? thank you

Nope. 25' is conductor length. Best option is ocpd in meter room.

 

[augie47]

I only see two options: Apply one of the appropriate 240.21(C)(3) tap rules (10 ft/25 ft) by adding OCP in the meter room, or move the transformer to the end of the run which would allow you to size the conductors by the 90 amp primary OCP.