Link Break Disconnects

[power82]

On distribution systems, in areas of higher fault current, or higher system voltages, especially on heavily loaded UG laterals, construction crews would rather disconnect the load using a link break disconnect, as opposed to opening the cutout door. The question which has come up is whether this should be implemented on OH laterals as well. Using a link break disconnect is obviously more expensive. Would you have any input on your practices and the reasons why?

 

[jbartos]

Suggestion: It depends who poses the question. Often, the construction crew follows the Firm practices. There is then a very little choice left. Reasons: increased safety and cost savings.

 

[busbar]

“…opening the cutout door” very likely has no intended interrupting rating, and may be for unloaded-circuit isolation only. This might be verified though cutout-manufacturer’s published data.

 

[stevenal]

Please explain what you mean by "link break." Cutouts and solid blades with the proper ears can be opened under load with the aid of a load buster tool. I think S&C and AB Chance supply them.

 

[jbartos]

Suggestion: Visit

http://www.usace.army.mil/publications/armytm/tm5-684/chap8.pdf

for:
b. Periodic inspection of fuse links in distribution cutouts. These fuse links may require periodic inspections,
since corrosion of the lower terminal of the fuse link (generally a flexible cable) at the lower open-end of the fuse holder may cause breakage or melting at this point, rather than in the currentresponsive element. Link-break cutouts are particularly susceptible since their link-break mechanisms impose a mechanical strain on fuses.

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