K8MHZ
Senior Member
- Occupation
- Electrician
The line is there that in case of copper earth conductor, it is not necessary to use more than 100 Sq.mm.
'Not necessary' is not the same as 'maximum allowed'.
The line is there that in case of copper earth conductor, it is not necessary to use more than 100 Sq.mm.
'Not necessary' is not the same as 'maximum allowed'.
Yes, I was. I couldn't see anybody making a rule for a maximum sized EGC allowed.I think the OP was hoping you might have a copy of the Indian electrical standards.
So. The NEC does not have a "maximum allowed" EGC either. I could run a 250kcmil for a 15A circuit.
Originally Posted by T.M.Haja Sahib
Whereas the Indian NEC imposes a limit on the maximum size of EGC, the US NEC imposes none....
I'm not the one that said either had a maximum allowed. TM said the Indian Electrical Code had a maximum size allowed, not me. I looked through the (copyrighted) code book he posted a link to and found no limits on the maximum size of an ECG.
My bad. I missed that in the OP.:ashamed1::slaphead:
Some day I will learn to read closer, but I guess this ain't it.
Wet noodle lashes to you!!!
How do you know that any of that mess is copper?
But there is a conflict between the two codes. The Indian code permits not to increase the copper earth conductor beyond 100 sq.mm size, whereas the U.S code does not. That is the point here. Isn't it ?'Not necessary' is not the same as 'maximum allowed'.
But there is a conflict between the two codes. The Indian code permits not to increase the copper earth conductor beyond 100 sq.mm size, whereas the U.S code does not. That is the point here. Isn't it ?
I think you are talking about maximum size of grounding electrode conductor. There is no such thing in NEC. There is minimum size required but you can always use a larger size.
Table 250.66 only lists the size of 3/0 (which 100 mm? falls between 3/0 and 4/0 AWG) as the largest minimum size grounding electrode conductor ever needed. Nowhere does it say it is the maximum size allowed.
So, it means this:
Per US NEC, it is not necessary to use copper ground conductor of size beyond 3/0. (no matter what the conductor size is).
Per Indian NEC, it is not necessary to use copper ground conductor of size beyond 100 Sq.mm. (no matter what the conductor size is).
So, it means this:
Per US NEC, it is not necessary to use copper ground conductor of size beyond 3/0. (no matter what the conductor size is).
Per Indian NEC, it is not necessary to use copper ground conductor of size beyond 100 Sq.mm. (no matter what the conductor size is).
Even if GEC were accidentally cut in a grounding system per US NEC, protection for short circuit is still available through EGC still connected to the neutral. But if the earthing conductor in a grounding system per Indian NEC were cut, protection for short circuit is lost. So on this basis, I think providing a upper limit for minimum size copper conductor as 100 sq.mm per Indian NEC does not seem to be correct.Other than the equipment grounding conductor that K8MHZ brought up, Yes - where are you going with this?
Even if GEC were accidentally cut in a grounding system per US NEC, protection for short circuit is still available through EGC still connected to the neutral. But if the earthing conductor in a grounding system per Indian NEC were cut, protection for short circuit is lost. So on this basis, I think providing a upper limit for minimum size copper conductor as 100 sq.mm per Indian NEC does not seem to be correct.
I do not know Indian code.
In NEC, GEC is not intended to carry short circuit current. Your likelihood of ever having one able to carry enough current to allow for operation of an overcurrent device is not that great either.
So what does the GEC do then? ...
(2008)250.4A1 said:Electrical System Grounding. Electrical systems that
are grounded shall be connected to earth in a manner that
will limit the voltage imposed by lightning, line surges, or
unintentional contact with higher-voltage lines and that will
stabilize the voltage to earth during normal operation.
After 40+ years in the business I still don't know what a "line surge" is. I also don't know how driving a ground rod will "limit the voltage to ground".(2008)250.4A2 said:Grounding of Electrical Equipment. Normally non–
current-carrying conductive materials enclosing electrical
conductors or equipment, or forming part of such equipment,
shall be connected to earth so as to limit the voltage
to ground on these materials.
Un-documented, un-proven, personal opinion:So what does the GEC do then? ...
After 40+ years in the business I still don't know what a "line surge" is. I also don't know how driving a ground rod will "limit the voltage to ground".
I don't think us Americans have this grounding thing figured out yet.
ice