Grounding in Mobile/Manufactured homes

[sirjonathon]

Hello!

can anyone share a couple pics of how they properly grounded their wood stove to the frame/chassis of their home? WA state law requires #8 copper wire and must use a paint penetrating washer to be installed where connected to the frame.

 

[begreen]

The stove needs to be bolted to the floor in mobiles. Would the inspector accept a connection at the foot of the leg bolt assuming that area is cleared of paint?

 

[rwhite]

Is an OAK required? You could always attach a ground and run it inside the OAK duct then over to the frame

 

[john26]

I would recommend 12ga or larger wire and at least a 10/32 screw. There is a calculation in NFPA70 for surface area on ground connection typically screw size I can't remember the article number but typical 20 amp circuits usually calculate to a 10/32 screw.

 

[sirjonathon]

Is an OAK required? You could always attach a ground and run it inside the OAK duct then over to the frame

an outside air intake is required, but i was going to run it directly outside since i will be right next to an outside wall.

 

[sirjonathon]

I would recommend 12ga or larger wire and at least a 10/32 screw. There is a calculation in NFPA70 for surface area on ground connection typically screw size I can't remember the article number but typical 20 amp circuits usually calculate to a 10/32 screw.

Good to know thanks! will i need to screw directly into the steel frame of the house? or can it clamp onto it?

 

[sirjonathon]

The stove needs to be bolted to the floor in mobiles. Would the inspector accept a connection at the foot of the leg bolt assuming that area is cleared of paint?

Yeah i think ive got that part down. the guide provided says to attach it to the bolt you use to bolt the stove to the floor.. but not sure what to do once i have the wire down at the frame of the house

 

[john26]

I would recommend to drill and tap the frame. There are clamps you can use for grounding usually expensive crimp a stay-con eye on the end of the wire and use a 10/32 screw into the frame. I recommend a drill tap combo they are good for a few holes just run it slow in a drill.
Amazon product ASIN B016FMEZSO

 

[begreen]

Yeah i think ive got that part down. the guide provided says to attach it to the bolt you use to bolt the stove to the floor.. but not sure what to do once i have the wire down at the frame of the house

Bolt the other end to the frame. If there isn't a close by existing hole you can use you will have to drill one.

 

[rwhite]

Yeah i think ive got that part down. the guide provided says to attach it to the bolt you use to bolt the stove to the floor.. but not sure what to do once i have the wire down at the frame of the house

Can't you get a long enough bolt to run clean through the floor? The just jam nut a ground on that and run to frame?

 

[brenndatomu]

Good to know thanks! will i need to screw directly into the steel frame of the house? or can it clamp onto it?

I'd clamp it...not saying this is the clamp you have to use...there are lots of options out there though...some cheaper than others.

https://www.lowes.com/pd/Sigma-Electric-ProConnex-1-2-in-Beam-Clamp-Conduit-Fitting/1002121

 

[john26]

I definitely would not use that clamp it is not at all designed for grounding purposes and definitely not UL listed for grounding. typically when grounding to building steel CAD welding is the preferred method that would be over kill here. I was recently tasked with changing grounds to building steel in a manufacturing facility mandated by a safety audit, the clamps were like regular beam clamps like shown above, we had to purchase grounding clamps at $96 a piece. if you are going to clamp it you need use something like this below. Trailer frames are typically soft steel drill and tap would be the cheapest method.
Amazon product ASIN B00UKG9032

https://rexel-cdn.com/Products/4C635C32-6B06-4AE5-AC7A-A50204C6AAF2/4C635C32-6B06-4AE5-AC7A-A50204C6AAF2.pdf

 

[brenndatomu]

not at all designed for grounding purposes and definitely not UL listed for grounding.

drill and tap would be the cheapest method.

You have UL listed grounding bolts for that then?

 

[john26]

No that is not necessary according to NFPA 70 Article 250.8A(5) All though many inspectors want a Green ground screw code does require a green screw with hex head where there are multiple terminals present.
250.8 Connection of Grounding and Bonding Equipment. (A) Permitted Methods. Grounding conductors and bonding jumpers shall be connected by one of the following means: (1) Listed pressure connectors (2) Terminal bars (3) Pressure connectors listed as grounding and bonding equipment (4) Exothermic welding process (5) Machine screw-type fasteners that engage not less than two threads or are secured with a nut (6) Thread-forming machine screws that engage not less than two threads in the enclosure (7) Connections that are part of a listed assembly (8) Other listed means (B) Methods Not Permitted. Connection devices or fittings that depend solely on solder shall not be used.
Since this is a mobile home article 550.16 applies according to that it should be grounded in the main panel
(1) Exposed Non–Current-Carrying Metal Parts. All exposed non–current-carrying metal parts that may become energized shall be effectively bonded to the grounding terminal or enclosure of the distribution panelboard. A bonding conductor shall be connected between the distribution panelboard and accessible terminal on the chassis.