Why GFCIs on 240 volt equipment?

tortuga

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One thing to consider is if the rest of the world codes/standards are moving towards RCD's (GFCI like devices) also?
I dont know.

If we now have to GFCI everything
then why not change 210.6(A) to read '150 Volts to ground' everywhere it says '120 volts between conductors'


Right, but nothing in the code stops me from running 12/3 UF 1,500 feet to a pool house.
LOL I think I had to go troubleshoot that once.
If you install a wire so long the breaker wont trip I think you would be in violation of 110.10.
 

mbrooke

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One thing to consider is if the rest of the world codes/standards are moving towards RCD's (GFCI like devices) also?
I dont know.
True, there is that. Though countries where EGCs were more likely to be absent got them first. Ie, mainland EU:


As with most types of European sockets, Schuko sockets can accept Europlugs. Schuko plugs are considered a very safe design when used with Schuko sockets, but they can also mate with other sockets to give an unsafe result.
If we now have to GFCI everything
then why not change 210.6(A) to read '150 Volts to ground' everywhere it says '120 volts between conductors'
That day will probably come...

LOL I think I had to go troubleshoot that once.
If you install a wire so long the breaker wont trip I think you would be in violation of 110.10.


110.10 Circuit Impedance, Short-Circuit Current Ratings, and
Other Characteristics. The overcurrent protective devices, the
total impedance, the equipment short-circuit current ratings,
and other characteristics of the circuit to be protected shall be
selected and coordinated to permit the circuit protective devices
used to clear a fault to do so without extensive damage to
the electrical equipment of the circuit. This fault shall be
assumed to be either between two or more of the circuit
conductors or between any circuit conductor and the equipment
grounding conductor(s) permitted in 250.118. Listed
equipment applied in accordance with their listing shall be
considered to meet the requirements of this section.
But the intent could be argued as survivability of the OCPD and conductors, not that the total impedance shall be low enough to facilitate operation of an OCPD in 1 second or less.
 

paulengr

Senior Member
True, there is that. Though countries where EGCs were more likely to be absent got them first. Ie, mainland EU:






That day will probably come...







But the intent could be argued as survivability of the OCPD and conductors, not that the total impedance shall be low enough to facilitate operation of an OCPD in 1 second or less.
It’s a different problem.

At the distribution level we have long treated shorts, overcurrent, and ground fault different. They ARE different. Sometimes overcurrent works for everything but most of the time you need to address each individually, particularly when straight inverse time is inadequate. It’s convenient when they are the same but the default on modern electronic breakers is LSIG or LIG for a reason.

It is really eye opening when you start running calculations and realize most of the time instantaneous won’t catch shorts, and inverse time is either unacceptably slow or wont trip at all on ground faults.

SCCR is now required in many places. We are not far from evolving to ground faults.
 

mbrooke

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United States
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It’s a different problem.
No different then all the 2 prong tools and broken EGCs on cord caps in the states. Both of which put GFCIs into the code.

At the distribution level we have long treated shorts, overcurrent, and ground fault different. They ARE different. Sometimes overcurrent works for everything but most of the time you need to address each individually, particularly when straight inverse time is inadequate. It’s convenient when they are the same but the default on modern electronic breakers is LSIG or LIG for a reason.

It is really eye opening when you start running calculations and realize most of the time instantaneous won’t catch shorts, and inverse time is either unacceptably slow or wont trip at all on ground faults.

SCCR is now required in many places. We are not far from evolving to ground faults.
So why should code mandate only one solution when there are several?
 

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
There is also the issue of folks running circuits that are to long without upsizing the EGC which is being used as a case to push GFCIs and GFPs for all circuits and feeders.
IMHO this should be an optional approach for long circuits and feeders.

You should be required to increase the size of the egc, or use ground fault sensitive ocpd, or prove under engineering supervision that some other selected method provides an effective ground fault clearance.

But it makes no sense to require both.
 

mbrooke

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United States
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IMHO this should be an optional approach for long circuits and feeders.

You should be required to increase the size of the egc, or use ground fault sensitive ocpd, or prove under engineering supervision that some other selected method provides an effective ground fault clearance.

But it makes no sense to require both.
Code should give options. But if you want my honest opinion, I'll take more copper (or AL) any day over a GFCI. Electronics can and do fail.
 
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