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Electrical Inspections Contains discussions about electrical systems. This includes receptacles, panels, wiring, etc.

 
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  #1  
Old 6/5/10, 2:49 PM
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Question detached panel,

Hi there,, correct me if I am wrong !! I need to understand before I say it's in need of repair / evaluation in the report.

The place is in the county, no codes apply. Manufactured home has meter and SE panel on pole in yard. 4-wire feed to home, no problem.

On the back side of the same pole is smaller panel with 3-60 Amp breakers for various outbuildings. Power for this panel is supplied from breaker in SE panel, 3 wire feed thru liquid-tight flex conduit. The one buss bar is bonded to the panel on the inside and contains the various grounded as well as the bonding conductor.

As I understand, the smaller panel should have a 4-wire feed, separate the grounded and grounding bus bars and their conductors, and remove bonding conductor.

If the conduit hadn't created a metallic pathway between the boxes, it would have been acceptable by adding a GEC. ?

Thanks,
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  #2  
Old 6/5/10, 7:18 PM
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Default Re: detached panel,

Here's the 2008 NEC wording on when LFMC can be used as an equipment grounding conductor. Does your installation comply?

Quote:
250.118 Types of Equipment Grounding Conductors.
The equipment grounding conductor run with or enclosing the circuit conductors shall be one or more or a combination of the following:
FPN: For effective ground-fault current path, see 250.2 Definition.
(1) A copper, aluminum, or copper-clad aluminum conductor. This conductor shall be solid or stranded; insulated, covered, or bare; and in the form of a wire or a busbar of any shape.
(2) Rigid metal conduit.
(3) Intermediate metal conduit.
(4) Electrical metallic tubing.
(5) Listed flexible metal conduit meeting all the following conditions:
a. The conduit is terminated in listed fittings.
b. The circuit conductors contained in the conduit are protected by overcurrent devices rated at 20 amperes or less.
c. The combined length of flexible metal conduit and flexible metallic tubing and liquidtight flexible metal conduit in the same ground return path does not exceed 1.8 m (6 ft).
d. Where used to connect equipment where flexibility is necessary after installation, an equipment grounding conductor shall be installed.
(6) Listed liquidtight flexible metal conduit meeting all the following conditions:
a. The conduit is terminated in listed fittings.
b. For metric designators 12 through 16 (trade sizes through ½), the circuit conductors contained in the conduit are protected by overcurrent devices rated at 20 amperes or less.
c. For metric designators 21 through 35 (trade sizes ¾ through 1¼), the circuit conductors contained in the conduit are protected by overcurrent devices rated not more than 60 amperes and there is no flexible metal conduit, flexible metallic tubing, or liquidtight flexible metal conduit in trade sizes metric designators 12 through 16 (trade sizes through ½) in the grounding path.
d. The combined length of flexible metal conduit and flexible metallic tubing and liquidtight flexible metal conduit in the same ground return path does not exceed 1.8 m (6 ft).
e. Where used to connect equipment where flexibility is necessary after installation, an equipment grounding conductor shall be installed
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Old 6/5/10, 9:04 PM
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Default Re: detached panel,

250.118 Types of Equipment Grounding Conductors.
The equipment grounding conductor run with or enclosing the circuit conductors shall be one or more or a combination of the following:
FPN: For effective ground-fault current path, see 250.2 Definition.
(1) A copper, aluminum, or copper-clad aluminum conductor. This conductor shall be solid or stranded; insulated, covered, or bare; and in the form of a wire or a busbar of any shape.
(2) Rigid metal conduit.
(3) Intermediate metal conduit.
(4) Electrical metallic tubing.
(5) Listed flexible metal conduit meeting all the following conditions:
a. The conduit is terminated in listed fittings. unknown
b. The circuit conductors contained in the conduit are protected by overcurrent devices rated at 20 amperes or less. no, 3 @ 60 Amp ea.
c. The combined length of flexible metal conduit and flexible metallic tubing and liquidtight flexible metal conduit in the same ground return path does not exceed 1.8 m (6 ft). yes
d. Where used to connect equipment where flexibility is necessary after installation, an equipment grounding conductor shall be installed.
(6) Listed liquidtight flexible metal conduit meeting all the following conditions:
a. The conduit is terminated in listed fittings.
b. For metric designators 12 through 16 (trade sizes through ½), the circuit conductors contained in the conduit are protected by overcurrent devices rated at 20 amperes or less.
c. For metric designators 21 through 35 (trade sizes ¾ through 1¼), the circuit conductors contained in the conduit are protected by overcurrent devices rated not more than 60 amperes and there is no flexible metal conduit, flexible metallic tubing, or liquidtight flexible metal conduit in trade sizes metric designators 12 through 16 (trade sizes through ½) in the grounding path.
d. The combined length of flexible metal conduit and flexible metallic tubing and liquidtight flexible metal conduit in the same ground return path does not exceed 1.8 m (6 ft).
e. Where used to connect equipment where flexibility is necessary after installation, an equipment grounding conductor shall be installed

I referred to qualified electrical contractor.
The SE panel and interior hookup in the mfg. home looked prof. done, but the panel in question had all the earmarks of a Harry HomeOwner install.
Thanks.
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Old 6/5/10, 9:49 PM
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Default Re: detached panel,

250.118(5) is for Flexible Metallic Conduit (FMC) not liquid tight (LFMC). That would be covered under the bolded section in my first post 250.118(6).

Also there are two different trade sizes listed in that section so you would need to know the size of the LFMC to know if it qualifies as an EGC.
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Old 6/6/10, 11:26 AM
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Default Re: detached panel,

Prior to the 08 NEC outbuilding could be feed with a 3 wire feeder provided there was no metallic path like a phone, cable or water line back to the originating structure. The panels would then be wired like a service with the bond between the neutral and ground installed.
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