When are hi pot tests done? before or after installation?
When are hi pot tests done? before or after installation?
(OP)
When are high pot tests done and what is the specific reason they are done? We are going to install new multiple runs of medium voltage cables and one of the construction tasks are these hi pot tests. Are the tests done before or after the installation? How long does a typical test take?






RE: When are hi pot tests done? before or after installation?
RE: When are hi pot tests done? before or after installation?
There is a modern solution to this, utilizing very low frequency AC, which can assess the cables, while avoiding cable damage. Often these modern test sets can also perform a tan delta (power factor) test, which gives more information about the quality of each cable / accessory tested. The test time can be based on various specifications, but in general is between 10-20 minutes per cable.
There is a member on this forum that may chime in that is an expert in this matter.
RE: When are hi pot tests done? before or after installation?
Is there a problem with these?
RE: When are hi pot tests done? before or after installation?
RE: When are hi pot tests done? before or after installation?
RE: When are hi pot tests done? before or after installation?
I generally only ask for hi-pot tests post installation. Occasionally I have asked for a test while the cable is still on the reel, but this is only if the installation is arduous and the cable is supplied by someone other than the installer (ie an Owner-supplied cable). If the cable is supplied, installed and terminated by the installer all I care about is the final test.
An 'arduous' installation may include the following;
- large and long cable (ie $$$)
- direct buried cable
- vertical installation (in a mine)
Also a reel test will usually be done without stress cones installed, and depending upon the test voltage, corona discharge might make the results difficult to interpret.
The time required to take the test can vary considerably depending upon the voltage and the length of the cable. For short runs in a typical industrial plant I have seen tests done as quickly as one phase per 1/2 hour. I have also tested a 11km cable to 125kV that took one day per phase, due to capacitance charge/discharge time constants of the cable. Of course the above times do not include travel and or set up time.
Regards,
GG
"Wish I didn't know now what I didn't know then." -- Bob Seger
RE: When are hi pot tests done? before or after installation?
If you are referring to hi-pot testing of the cable on the reel prior to installation, no it is not an "industry standard" by any means. It is generally used when the cable is owner-furnished for installation by a contractor.