You don't use it for the electrical ground. NEC Section 250.121b states “The structural metal frame of a building or structure shall not be used as an equipment grounding conductor.” and also, Section 90.1. it'll need a low impedance ground. But again, check with your local electricians.
You don't use it for the electrical ground. NEC Section 250.121b states “The structural metal frame of a building or structure shall not be used as an equipment grounding conductor.” and also, Section 90.1. it'll need a low impedance ground. But again, check with your local electricians.
Phil
Phil, maybe you should quit now and stop giving advice. Just because you can read the code doesn't mean you can understand it. Within the grounding section is probably the least understood wording in the NEC- even for electricians. The grounding electrode system includes, underground water pipe if metal, eufer ground conductor tied to the lowest rebar in the foundation system at a point near the service location, ground rods if the eufer is not present, and metal parts of a metal building. In fact, since this will probably be multiple containers if I understand the OPs intent? it would be required to bond all of them together and back to the service location. Bonding is an extension of the grounding section and is also misunderstood often. For instance, if your incoming water system is plastic, but your interior water system is metal- copper, galvanized, etc... it must be bonded to the service ground. In the same way that all metal electrical boxes must be grounded in a code approved manner.
Last edited by Sheister; 01/27/24.
Never underestimate your ability to overestimate your ability.
As I said - understand what you are reading. The metal frame of a building should not be used as a grounding conductor is not the same as grounding the metal building , bonding the metal frame, or using it as a part of the grounding electrode system if it is tied to the foundation with metal. That change is a clarification of the original code. What they are saying is you can't use the building to tie a ground to , such as having a welding machine in a corner of the building and needing to have a ground to connect to. You can't simply ground to the building frame, even if it is bonded back to the original service, and use it as a ground conductor. Your ground conductor must be carried with the circuit conductors back to the source of power. This doesn't preclude that the building should not be grounded- just the opposite- the metal frame must be bonded to the ground at the service in cases where it is not attached to a grounding source, like bolts holding it down to a concrete slab which is in contact with earth. If a metal building is not bolted or otherwise in a recognized contact with earth ground then the metal frame must be bonded back to the service at some point and continuously so a short to the metal doesn't create a difference of potential between the metal building and other grounded parts.
Never underestimate your ability to overestimate your ability.
I am starting on electrical for my shipping container cabin. I have studded the outside with metal studs and plan to run my electrical outside to junction boxes.
Is there a code for height of receptical boxes off floor?
I am curious about the terms you stated "you have studded the outside"? If you are running the studs on the outside are they subject to weather before you install whatever sheathing and water proofing you are planning on installing later? If so, electrical boxes and most electrical connections are not rated for exterior use and are not to be exposed to moisture. Corrosion can occur and you will have all kinds of problems once this happens.
Never underestimate your ability to overestimate your ability.
What is the thickness of the interior styrofoam insulation? I've worked with ICF forms walls before that have insulation on the interior approximately 1 1/2" thick. If you use standard 4 x 4 x 1 1/2 " boxes, mounted against the wall the come out flush to the front of the insulation and you can run your electrical in the foam by cutting a channel in the foam to run your electrical wiring . The couple I worked in used 2 x 2 wood furring strips ( 1 5/8" finish size) on the wall at 16" centers or 24" centers to mount wall finish to- usually sheetrock. Then they would cut the hardboard insulation to fit between the furring strips to fit tightly. They would use various tools to cut the channels for wiring- heated wiring foam cutters, saws, or small handheld chainsaws - and then stuff the wiring into the channel they created. Pretty neat, simple, and fast system for running electrical and plumbing and doesn't take up much room on the interior. Also meets code as long as you use nail plates where you pass through the furring strips.
Never underestimate your ability to overestimate your ability.
ADA (American Disability Act) code used to be 18" for outlets if you're really concerned about it. But I've been retired now for 6 years and haven't kept up on it. Romex through metal studs need to have bushed pass throughs and screw guards on the front of the stud so drywall screws don't get the romex.
It isn't what happens to you that defines you, it's what you DO about what happens to you that defines you!
This to me looks like a monkey having congress with a football.
I have the wire protectors for the studs, but I am not sure the flexible conduit with wire inside wouldn’t be better?
I plan to put my main breaker box on the end of the container like in the video, but would prefer to run my power through the stud walls on outside and then into place at each outlet.
My design splits the container in half with master bathroom in middle serving master bedroom and utility closet 2nd bath serving living area against the master bathroom wall.
i have multiple vents and will vent both bathrooms but Montana humidity runs pretty low- in the teens most of this winter. Where the cabin goes is on the leeward side of the mountain.
Insulating inside and outside with the fans should reduce condensation on the container. I plan to insulate the ceiling and then the attic with the roof structure.
Insulating the floor is a little more challenging, but I should be able to, once it is on the foundation.
I widened the center of the container 22 inches to meet plumbing code, which makes wiring that side a little more challenging.
The styrofoam adds 2 inches on the inside of each wall but fits the corrugation of the container.
Can you explain how running the electrical inside the wall would not be to code?
If I could reduce the size of a pic, I would post a couple up.
Installing the electrical on the outside wall is legal, I'm just offering a way to save a bunch of time and issues. Depending on what kind of elbows you are considering, an emt 90 won't fit in a 4" wall without protruding on the inside. Not sure what other 90s you are consdiering, so I'm a bit confused on that part..And you will need to protect the wire running through it with correct connectors and bushings or other approved means. In the end, you still need a box on the inside wall to house the receptacle, switch, or whatever device and terminations you plan on using. A 4 x 4 x 1 1/2 " box works perfect for this and then you add a plaster ring for the device and sheetrock over it. Either way you have a box on the inside and if the insulation you are talking about using is 2" deep on the high end of the corrugation, you can run all your electrical inside and save a number of steps. Not sure how else to explain it unless you were to give me a call and I would like to see the corrugated insulation you are planning on using to see if this method would work.
Bob
Never underestimate your ability to overestimate your ability.
After putting 4-plex outlets @ 48" every 3' in my 24x30 shop, I'd now do them @ 52". 48" is right where everything 4x8 covers. I have 4 4-plex outlets in the ceiling as well and drop-down extension cords. The ceiling outlets/drop-downs get 10x more use than any of the wall outlets as you never have to step over extension cords.
I can walk on water.......................but I do stagger a bit on alcohol.
Thanks all for the insights. The insofast is the foam panels in the video.
My idea was to use a box on inside and a box on outside and bolt those together, but several comments about the code made me say 90 elbow.
If the flex conduit wiring works l can certainly do that or if required I can do full conduit on outside. I am disinclined to run the wiring on inside.
