14kv Overhead Line Tap

[richanton]

I have to run temporary power lines via a line tap of an existing 14kv overhead line. Are there special tap kits available for this.

A second question is do any utilities require a 14kv disconnect either at the point of tap or at the other end on the primary side of the pole transformers. I know NEC 450 identifies primary and secondary protection requirements, but it seems to me that pole transformers normally don't have primary disconnects.

 

[jbartos]

Suggestion. The overhead transformers (pole transformers) do not have disconnects; however, they do have protectors. Check with your local Utility what exactly is required. It may be a fused disconnect.

 

[jghrist]

Normally, a tap would comprise a deadend of the tap line on two strain insulators and jumpers to the main line. The jumper could be an extension of the tap line thru the deadend clamp that connects the tap line to the strain insulator. Connection to the main line could be with parallel groove compression connectors or, if the tap may need to be periodically disconnected, with hot-line clamps connected to a stirrups (loop of solid conductor connected to the main line with a compression connector). The neutral would normally be connected with a parallel groove connector because it wouldn't need to be disconnected.

If the tap is of significant length and will expose the main line to faults, a fused cutout would be used on the tap.

If conventional transformers are used, fused cutouts would be installed at the transformer. If CSP (Completely Self Protected) transformers are used, they would be connected to the tap line with hot line clamps to allow disconnection.

 

[jbartos]

Suggestion: There are T transmission seen; many of them in textbooks for calculation and demonstration purposes. However, the practical transmission lines or substations with three transmissions connection have breakers installed there.

 

[richanton]

Thanks to all for the help. Overhead lines are not my normal area of expertise.