Outside feeder

[hhsting]

I have panelboard with breaker inside building feeding trailer outside the building. The trailer disconnect is mounted right on outside wall of the building. From the trailer disconnect to trailer is within 30 feet. The trailer has two panelboards. Please see attached picture

Would the grounding electrode system mentioned in 250.32(A) be at the two panelboards or at the trailer disconnect mounted outside wall of building?

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[petersonra]

are you asking where the connection should be made? or where the GES is physically located?

seems to me that absent a proven 25 Ohm connection, two ground rods are required.

 

[augie47]

IMO, it being a temporary trailer, I would inspect it under Art 550 and since it is supplied by a feeder, not require an electrode other than the supplemental one shown by engineered drawings.

 

[hhsting]

are you asking where the connection should be made? or where the GES is physically located?

seems to me that absent a proven 25 Ohm connection, two ground rods are required.

The question i have is should the grounding electrode conductor be connected to trailer disconnect or at the trailer panelboard? Which one

 

[petersonra]

IMO, it being a temporary trailer, I would inspect it under Art 550 and since it is supplied by a feeder, not require an electrode other than the supplemental one shown by engineered drawings.

Article 550 only applies to dwelling units. this structure does not appear to be a dwelling unit.

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.

Manufactured Home. A structure, transportable in one or
more sections, which in the traveling mode is 2.4 m (8 ft) or
more in width or 12.2 m (40 ft) or more in length, or when
erected on site is 29.77 m2 (320 ft2) or more is built on a
permanent chassis and is designed to be used as a dwelling with
or without a permanent foundation, whether or not connected
to the utilities, and includes plumbing, heating, air conditioning,
and electrical systems contained therein. The term manufactured
home includes any structure that meets all the
requirements of this paragraph except the size requirements
and with respect to which the manufacturer voluntarily files a
certification required by the regulatory agency. Calculations
used to determine the number of square meters (square feet)
in a structure are based on the structure's exterior dimensions
and include all expandable rooms, cabinets, and other projections
containing interior space, but do not include bay windows
[501:1.2.14]. For the purpose of this Code and unless otherwise
indicated, the term mobile home includes manufactured homes
and excludes park trailers defined in Article 552.4.

Mobile Home. A factory-assembled structure or structures
transportable in one or more sections that are built on a
permanent chassis and designed to be used as a dwelling without
a permanent foundation where connected to the required
utilities and that include the plumbing, heating, airconditioning,
and electrical systems contained therein.

 

[augie47]

OP is on the '17 Code which states the following:
550.4 General Requirements. (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 differ‐ ent voltage is required by either design or available power supply system, adjustment shall be made in accord

 

[hhsting]

OP is on the '17 Code which states the following:
550.4 General Requirements. (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 differ‐ ent voltage is required by either design or available power supply system, adjustment shall be made in accord

Ok but where would grounding electrode connection should be? In the sketch its shown at 200A disconnect. Should it be at the two 200A panelboards?

Another thing NEC 2017 Section 550.33(A)(2) says feeder conductors comply per 250.32(B) no mention of 250.32(A)??

 

[augie47]

Repeating my comment in Post #3, MY OPINION, is that it is a 550.4 application with a feeder and NO grounding electrode is required. Apparently you have engineered drawings calling for an auxiliary electrode at the disconnect which is allowed by 250.54

 

[hhsting]

Repeating my comment in Post #3, MY OPINION, is that it is a 550.4 application with a feeder and NO grounding electrode is required. Apparently you have engineered drawings calling for an auxiliary electrode at the disconnect which is allowed by 250.54

NEC 2017 Section 550.32(A) would say GEC require at 200A disconnect

 

[augie47]

550.32(A) is for Services. You don't have a service, you have a feeder.

 

[hhsting]

550.32(A) is for Services. You don't have a service, you have a feeder.

i thought 2017 NEC section 550.32(A) says if service equipment is remote then disconnect is required within 30 feet of trailer and that disconnect need to have grounding as mentioned in 250.32?

 

[SSDriver]

i thought 2017 NEC section 550.32(A) says if service equipment is remote then disconnect is required within 30 feet of trailer and that disconnect need to have grounding as mentioned in 250.32?

550.32 doesn't apply if it's a feeder. That section is for service equipment only. Your first post said it's being fed from a inside panel board, so it's a feeder.

 

[hhsting]

550.32 doesn't apply if it's a feeder. That section is for service equipment only. Your first post said it's being fed from a inside panel board, so it's a feeder.

Would service equipment grounding ever comply with 250.32 which about feeders?

See below 550.32(A) last paragraph