what is the difference between earthed and unearthed cable?
Answer Posted / e.k rajan nair
In 3phase earthed system, phase to earth voltage is
1.732times less than phase to phase voltage. therefore
voltage stress on cable to armor is 1.732times less than
votage stress between conductor to conductor. whre as in
unearthed system, (if system neutral is not grounded)
pahse to ground voltage can be equal to phase to phase
voltage. in such case the insulation level of conductor to
armor should be equal to insulation level of conductor to
conductor. as a thump rul we can 6.6KV UE cable is equal to
11k earthed cable ie 6.6/6.6kv UN cable can be used for
6.6/11kv earthed system. because each core of cable have
the insulation level to withstand 6.6kv so between core to
core insulation level will be 6.6kv+6.6kv = 11kv
| Is This Answer Correct ? | 26 Yes | 6 No |
Post New Answer View All Answers
Which motor connection is preferable star-delta or delta-star?
What are books to be referred for KPTCL exam?
What is the criteria for selecting the voltage classes of an AC Induction Motor.The KW rating above/below which ht/lt selection is made may be provided in details.
Give idea about General Engineering. From which book i can study this topic. Pl. reply me via email. My email is ravi@bhelhwr.co.in, also give the name of book/website, from where i can prepare it.
I have motor 1500 HP and , 4160 V , 60 HZ , then i need the rating of transformer which can feed that motor ??
How much should be the load percentage for 15kva Inverter and Iinut & I output load with Calculations
why core is useful for a transformer ?and also in its operation ?
how to calculate current and voltage in a same circuit?
What is electrical grounding?
do we use links in a dc circuit?if so what s its use in it?
What is installed in PAC that is control the humidity
what is p.s impedance measurement test in earthing transformer?
PLEASE TELL ME ABOUT QUESTION PAPER OF UPCL ENTERENCE EXAM.
An impedance of 100 ohms resistance and an unknown inductance is connected across the capacitor. The resulting impedance is a pure resistance of 500 ohms ifω = 10^5 rad/sec. calculate the values of inductor and capacitor.
What are factors to be considered while we selecting the Core Balance Current Transformer for Earth fault protection