Thank you for your replies, however the cable spec is :
Single conductor 5-15KV, 100% &133% insulation level.
My questions is
1- Do i have to order the insulation level depending on the status of grounding? Any standard for that?
2- Any explanations Why 33% and 73% more insulation, any...
Can anybody explain, what is the idea behind having 100% insulation level and 133% insulation level in testing XLPE, EPR medium voltage cables?
Thank you
HI davidbeach, ScottyUK
Thank you for your response,
According to CEC yes two grounds are connected to neutral, one at the outdoor transformer side (four 10feet rods bonded together), and the other ground is inside the building connected to the main panel, (ground rod bonded to the water...
- The primary of the transformer is delta and the star is solidly ground.
- Yes it is in Canada.
- Normally the outdoor transformer has its own ground, and the building has its own ground as well, by code how can we eliminate this current by connecting the building ground with the transformer...
Thanks,
however, the transformer is away from the building, and the main building panel is grounded via the armored of the tech cable feeding the panel from the transformer,
do you mean that we have to connect the water pipe (or the grounding rods) of the building to the main transformer...
i have an outdoor Transformer of 500KVA, 13.9 /.6 KV, The low voltage side Y is grounded by the transformer,and a feeder cable is connected to the main panel inside the building.
when i shut down the main panel, i found that there is a 0.9 amp flowing from the nuetral cable to the ground inside...
Thanks for your answers, my understanding that the phase tom earth voltages used are 120,240,277 & 347 which actually will obtain 208,416,480 &600volt respectively via phase to phase voltages. If so what's behind that? and why all these voltage varieties are used for? and how are they obtained...
I agree with scottyUK, however there must be C.Ts& V.Ts installed in the step up and step down switch yard (if AIS), otherwise how were these substation commissioned energized, further information's will be very useful
the resistivity of earthing system should be less than 1 ohm,embiding it in the concrete floor are subjected to many variables,i suggest to add some salts to the earthing rods in the yard to obtain the required resistivity