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by Levingston George, Lead Specialist Electrical Engineering Power Distribution.
A word to the wise!
Load break elbows have a limit.
I have worked for many USA utilities that specify and install medium voltage load break elbows for their main switching. I don't have a problem with that but there are some concerns that must be addressed, especially in northern climates.
First and foremost manufacturers of load break elbows don't usually mention this but there is a limit to the amount of times you can safely pull and park an elbow. The manufacturers in years past had a limit on how many times you could safely do this (50 times) before you should consider changing out the elbow body.
In colder climates, the dielectric grease freezes. Not to mention many underground linemen don't clean and re-apply the lubricating cable grease.
This can cause undue stress on the elbow body and it will eventually fail (Mr. Faradays cage fails).
So make sure you have your PPE on when you pull and park."
Cable Failures & Medium Voltage Connectors
Problems in medium voltage cable connectors are a common cause of accessory failure. Figure below shows a drawing of a load-break separable insulated connector (SIC). Within the load break elbow, bushing insert and bushing well that make up the SIC, there can be up to eight electrical contacts.
Usually problem MV connectors overheat, which is evidenced by a discoloured or burned conductor or cable insulation. Root cause of the failure is often improper installation including bad connector crimps, cross threading of the elbow probe, or a broken stud in the bushing well.
Category: HV Cable Jointing & Terminating