Hello, I have to calculate allowab

[Raj Adrika]

Hello,
I have to calculate allowable span length where there is 3 spans. From left, two spans consist of insulator with Slide, slide and fixed connector. The next right span has disconnect switch with expansion connector.The bus is 3.5" sch 40 AL with insulator TR287. I went through IEEE 605, there is calculation for the allowable span length only for the span with insulator. Did not find the case where there is switch and switch terminal loading to be considered for the span length calculation as per my understanding. Could anyone guide me how to calculate allowable span length is such case.

 

[RPMG]

I think that it's most common to support the switch and switch terminal from the supporting structure and not the conduit itself.

However, in general, you can compute an equivalent uniformly distributed load, conservatively, as 2 * WT / Span. In your case, this would be guessing the span to convert the switch weight into an equivalent added conduit weight, for use with your allowable span equation. I'm assuming that your allowable span equation is just a flexural stress check, reorganized as a max span length.