Mobile Home Grounding

Dennis Alwon

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Staff member
Location
Chapel Hill, NC
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Retired Electrical Contractor
I cannot find anything in art 550 that will allow a mobile home to have the grounding electrode conductor only in the service panel. Wouldn't you need to run a grounding electrode conductor to the inside panel also, as you would with a separate structure?
 
Just a stab in the dark, is a mobile home considered a vehicle, not a structure?
I never wired them but it is not a vehicle, IMO. It just seems odd if the service is 5' from the trailer.


I've never seen a MH with a GES connected to the mobile home panel, only to the service panel.
That was my thinking but where in the code is that allowed. Supposed the service was 50' away.
 
Is there anyone able to help on this.
First, the service can be further than 50', but you would need a disconnect within 30'.
If a disconnect is added, it has to have a GES there as well.
As for the grounding at the MH, the GES is at the service, which is remote from the mobile home.
A 4-conductor feed must be ran, with the EGC being insulated. At the MH main panel, the EGC lands on a grounding bus. The bus has to have a bonding jumper to the frame of the MH.
My take is the MH has to be anchored, and with the bonding jumper on the frame, the MH is grounded to Earth and no need for an additional GES.
 
I can't help as far as actual code wording but when I was an apprentice I helped a few Jmen who always put a jumper from the frame to the GES.
 
If you read the 2023 the service must be no more than 50' and within sight

(A) Mobile Home Service Equipment.
The mobile home service equipment shall not be mounted in or on the mobile home. The service equipment shall be rated not less than that required in accordance with 550.32(C), mounted in a readily accessible outdoor location, and within sight from the mobile home it serves. The mobile home service disconnect shall be permitted to be used as the emergency disconnect in accordance with 230.85.
 
I can't help as far as actual code wording but when I was an apprentice I helped a few Jmen who always put a jumper from the frame to the GES.
That's not code at all. In fact the code specifically says not to bond the EGC, or the metal frame, to the grounded conductor. Since the GES is bonded to the grounded conductor, I would think that would be a violation.
The bonding jumper from the frame to the main panel in the MH is usually done at the factory. We just have to make sure it is there and connected on both ends.
 
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