non grounded system extension

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Ponchik

Ponchik

Senior Member
Location
CA
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Electronologist
I was thinking about this today, can EMT be used to extend a non grounded system? It is in a residential garage lighting outlet and the customer wants it extended to another point and it will be done with EMT. Now my concern is if the system is not grounded, how is this safe?
 
A metal face plate as required by code has to be connected to an EGC.
Now, what is the difference between this installation and the installation that i have originally posted. Of course besides the obvious one is face plate one is EMT.
 
edward said:
A metal face plate as required by code has to be connected to an EGC.
Now, what is the difference between this installation and the installation that i have originally posted. Of course besides the obvious one is face plate one is EMT.
Click to expand...
This is...

250.86 Other Conductor Enclosures and Raceways.
Except as permitted by 250.112(I), metal enclosures and raceways
for other than service conductors shall be connected
to the equipment grounding conductor.

Exception No. 1: Metal enclosures and raceways for conductors
added to existing installations of open wire, knoband-
tube wiring, and nonmetallic-sheathed cable shall not
be required to be connected to the equipment grounding
conductor where these enclosures or wiring methods comply
with (1) through (4) as follows:
(1) Do not provide an equipment ground
(2) Are in runs of less than 7.5 m (25 ft)
(3) Are free from probable contact with ground, grounded
metal, metal lath, or other conductive material
(4) Are guarded against contact by persons
​

Exception No. 2: Short sections of metal enclosures or
raceways used to provide support or protection of cable
assemblies from physical damage shall not be required to
be connected to the equipment grounding conductor.

Exception No. 3: A metal elbow shall not be required to be
connected to the equipment grounding conductor where it
is installed in a run of nonmetallic raceway and is isolated
from possible contact by a minimum cover of 450 mm
(18 in.) to any part of the elbow or is encased in not less
than 50 mm (2 in.) of concrete.
Click to expand...
 
edward said:
I was thinking about this today, can EMT be used to extend a non grounded system? It is in a residential garage lighting outlet and the customer wants it extended to another point and it will be done with EMT. Now my concern is if the system is not grounded, how is this safe?
Click to expand...

NOTE: No EGC being added.

Little Bill said:
It seems that 250.130(C) would disagree with you.
Click to expand...

See above NOTE so 130(C) does not apply.

Smart $ said:
This is...
Click to expand...


Exception No. 1: Metal enclosures and raceways for conductors
added to existing installations of open wire, knoband-
tube wiring, and nonmetallic-sheathed cable shall not
be required to be connected to the equipment grounding
conductor where these enclosures or wiring methods comply
with (1) through (4) as follows:
(1) Do not provide an equipment ground
(2) Are in runs of less than 7.5 m (25 ft)
(3) Are free from probable contact with ground, grounded
metal, metal lath, or other conductive material
(4) Are guarded against contact by persons

He is extending not adding.
I assumed that it is not guarded.
 
jxofaltrds said:
...

He is extending not adding.
I assumed that it is not guarded.
Click to expand...
Logic precludes extending is adding.

May not be guarded now, or not planned to be... but now being aware of that requirement, it can be made to be guarded, or plans altered accordingly.
 
jxofaltrds said:
NOTE: No EGC being added.



See above NOTE so 130(C) does not apply.




Exception No. 1: Metal enclosures and raceways for conductors
added to existing installations of open wire, knoband-
tube wiring, and nonmetallic-sheathed cable shall not
be required to be connected to the equipment grounding
conductor where these enclosures or wiring methods comply
with (1) through (4) as follows:
(1) Do not provide an equipment ground
(2) Are in runs of less than 7.5 m (25 ft)
(3) Are free from probable contact with ground, grounded
metal, metal lath, or other conductive material
(4) Are guarded against contact by persons
Click to expand...

What does it mean "Guarded against contact..." i need to build a nonconductive enclosure around it? Above 7', 8', 10'... is considered guarded??

Does the installation have to comply with ALL of 1 through 4 or only one of the 4 requirements?
 
edward said:
What does it mean "Guarded against contact..." i need to build a nonconductive enclosure around it? Above 7', 8', 10'... is considered guarded??

Does the installation have to comply with ALL of 1 through 4 or only one of the 4 requirements?
Click to expand...

I think this means if an individual can come in contact with it then it must be grounded. Perhaps there are situations where there is no need for an egc so you can extend it but it must be protected or guarded so that persons cannot come in contact with the device.
 
edward said:
What does it mean "Guarded against contact..." i need to build a nonconductive enclosure around it? Above 7', 8', 10'... is considered guarded??

Does the installation have to comply with ALL of 1 through 4 or only one of the 4 requirements?
Click to expand...

All 4.

Dennis Alwon said:
I think this means if an individual can come in contact with it then it must be grounded. Perhaps there are situations where there is no need for an egc so you can extend it but it must be protected or guarded so that persons cannot come in contact with the device.
Click to expand...
I agree.
 
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