contractor trailer

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j rae

Senior Member
Hooking up a contractor trailer. I believe I need to run 4 conductor and they must all be insulated. Also drive a groung rod at the trailer to also bnd the fram and go to the ground bar in the service. What code number ?? THANKS
 

augie47

Moderator
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Location
Tennessee
Occupation
State Electrical Inspector (Retired)
I think you are correct per NEC. Historically I seldom see a ground rod at a construction trailer although I am at a loss as to what Code Article would exempt it.
 

augie47

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Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Need article number

IF you install a meter/disconnect/panel on a pole/post, by NEC definition, you have a "structure".
When you then install wiring to the construction trailer you are under the rules of 250.32 which would required a grounding electrode system at the 2nd "structure".
(There may be a Code Article with which I am not aware the views this otherwise)
 

Cavie

Senior Member
Location
SW Florida
A trailer is a trailer is a trailer. Mobil home, Manufactured home, Doesen't matter WHO is sitting in it. Wire it per 550. Outside disconnect not attached to, 2 spare spaces, ground rods, disconnect inside etc. Ground need not be insulated. Think SER cable. EMT.
 

RICK NAPIER

Senior Member
Location
New Jersey
Mobile Home.​

550.1 Scope. The provisions of this article cover the electrical conductors and equipment installed within or on mobile and manufactured homes, the conductors that connect mobile and manufactured homes to a supply of electricity, and the installation of electrical wiring, luminaires, equipment, and appurtenances related to electrical installations within a mobile home park up to the mobile home service-entrance conductors or, if none, the mobile home service equipment.

A factory-assembled structure or structurestransportable in one or more sections that are built on a permanent chassis and designed to be used as a dwelling withouta permanent foundation where connected to the required utilities and that include the plumbing, heating, air-conditioning, and electrical systems contained therein.


Mobile Home.


A factory-assembled structure or structurestransportable in one or more sections that are built on a permanentchassis and designed to be used as a dwelling without a permanent foundation where connected to the required utilitiesand that include the plumbing, heating, air-conditioning, and electrical systems contained therein.

With these two sections in mind a contractor's trailer does not appear to fall under 550 but 230 or 225 according to how it was fed.
 
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petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I don't see how a construction trailer can be classified as a "home" of any kind.

Structure. That which is built or constructed.

One could argue it is a structure, as it seems to fit the definition of a structure. However, I am not sure it is really a structure as one could argue it is manufactured and not constructed.

I also agree it is temporary and thus might well be wired per 590, which would seem to require you to provide a GES IAW article 250.
 
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petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I don't see how a construction trailer can be classified as a "home" of any kind.



One could argue it is a structure, as it seems to fit the definition of a structure. However, I am not sure it is really a structure as one could argue it is manufactured and not constructed.

I also agree it is temporary and thus might well be wired per 590, which would seem to require you to provide a GES IAW article 250.

I had to leave my keyboard and was unable to finish.

I think you only have to provide a GES if you decide it is a structure IAW with the article 100 definition, because article 250 says it requires one, and 590.2(A) says you have to follow all the normal requirements unless specifically modified in article 590.

I think the words "built" and "constructed" strongly imply something field assembled. a construction trailer was not field assembled. A pole stuck in the ground is.
 

renosteinke

Senior Member
Location
NE Arkansas
What's a "construction trailer?"

If you mean one of those job-site offices, then 550 contains language that make clear that the article applies, that such trailers are within the scope.

If you mean something with wheels, that's filled with your tools and transported around all day, then the NEC has limited application. Your rolling workshop is essentially a big appliance, and no ground rod is needed.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
What's a "construction trailer?"

If you mean one of those job-site offices, then 550 contains language that make clear that the article applies, that such trailers are within the scope.

If you mean something with wheels, that's filled with your tools and transported around all day, then the NEC has limited application. Your rolling workshop is essentially a big appliance, and no ground rod is needed.

My first thought was that the scope specifically excluded contractor job site offices.

550.1 Scope. The provisions of this article cover the electrical
conductors and equipment installed within or on mobile
and manufactured homes, the conductors that connect
mobile and manufactured homes to a supply of electricity, and
the installation of electrical wiring, luminaires, equipment, and
appurtenances related to electrical installations within a mobile
home park up to the mobile home service-entrance conductors
or, if none, the mobile home service equipment.

Interesting that they snuck in something farther down that seems to include it even though it is excluded in the scope.

(A) Mobile Home Not Intended as a Dwelling Unit. A
mobile home not intended as a dwelling unit ? for example,
those equipped for sleeping purposes only, contractor?s
on-site offices
, construction job dormitories, mobile
studio dressing rooms, banks, clinics, mobile stores, or intended
for the display or demonstration of merchandise or
machinery ? shall not be required to meet the provisions
of this article pertaining to the number or capacity of circuits
required. It shall, however, meet all other applicable
requirements of this article if provided with an electrical
installation intended to be energized from a 120-volt or
120/240-volt ac power supply system. Where different voltage
is required by either design or available power supply
system, adjustment shall be made in accordance with other
articles and sections for the voltage used.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
Bob,
I've managed to read right over that more than once. Thanks for the post.
(apparently septuagenarians need remedial reading courses)
 
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