acceptable values for Bus Ductor Test

[raadhatab]

Hi

Can any body tell me what are the acceptable code values for contact resistance (Bus Ductor Test) to bus sections, bus bars ..etc

Thank you

 

[juleselec]

I'm not sure there is a code for ductor tests on busbars (perhaps ANSI/NETA ATS, but I've never used it). The contact resistance of busbar joints will depend on the type of joint (bolted, clamped, welded, etc), contact area and pressure, and this will obviously differ across manufacturers.

You need to consult the manufacturer's recommendations on acceptable test results. That said, a max contact resistance of 10 micro-ohms is often quoted for large bolted joints.

 

[Zogzog]

The only thing in NETA is they should not vary by more than 50% between similar connections (Phases). But you should only see a few micro ohms.

 

[mmt019]

Zogzog pretty much has it correct EXCEPT NETA says to investigate values which deviate from those of similar bolted connections by more than 50% of the lowest value. Typically, the similar connections are the different phases and you are comparing the readings on A, B, and C phases. Readings should be in the micro-ohms.