Wiring MC cable into Load panel - Page 1
Forum section: electronics / general

author: free_electron
author_rank: Super Contributor
timestamp: July 15, 2020, 03:28:42 pm
content: I am trying to find out the correct way to terminate MC cable into a fuse panel.My main fuse panel is outside the house. There are two 3-inch pipes going . through the wall to inside the garage. So none of the typical knockouts in the sides is used. the panel is mounted on the outside wall and the pipes go from the back of the panel , directly through the wallCurrently there is standard romex coming from all parts of the house , through the metal pipes , into the fuse panel.I am running new cabling that is all MC ( Metal clad. that spiral coiled cable ) So how do i terminate the MC and then feed the individual wires through the two pipes into the loadbox. I need a kind of metal box that can properly terminate MC cable using knockouts , and convert that into a 3 inch pipe. Raco has something specifically designed for this purpose :. but i need one that has a 3inch conduit leaving ...this is the load box :https://www.homedepot.com/p/Square-D-Homeline-200-Amp-30-Space-42-Circuit-Outdoor-Ring-Type-Surface-Mount-Solar-Ready-Main-Breaker-Plug-On-Neutral-CSED-SC3042M200PS/206498055

author: MarkF
author_rank: Super Contributor
timestamp: July 15, 2020, 03:58:13 pm
content: How do the 3" conduits terminate on the inside now?Is there a junction box for each one of the conduits?

author: Monkeh
author_rank: Super Contributor
timestamp: July 15, 2020, 03:58:46 pm
content: Quote from: free_electron on July 15, 2020, 03:28:42 pmIt's a piece of sheet metal - make whatever size hole it is a 3 inch conduit requires.

author: free_electron
author_rank: Super Contributor
timestamp: July 15, 2020, 10:40:50 pm
content: Quote from: MarkF on July 15, 2020, 03:58:13 pmThe cables come from the joists and go down the wall. They do not go through the wall top plate. The cables (romex and alu wire) come through the pipe. By the way, that pipe is barely 1 inch long. it's more of a pass through .. All it serves is to bring the cables from the outdoor panel , through the stucco and drywall , into the wall cavity , where they go up and lay free hanging across the roof joists in the garage before disappearing through the fire-break into the house.The romex enters the breaker panel and is then stripped and wired. So it meets the code requirement in terms of marking ( or not marking.. This wire is pre-1987 so marking did not apply ) There is other aluminum cable (heavy gauge for 50 ampere) as well.I intend to replace all this old romex with MC cable through the attic and into a junction box per room. From the junction box Romex will disappear into the room walls. I have specifically bought MC cable that has the wires individually marked so they can be unsheathed ( aluminum outer jacket removed) and remainder fed directly though EMT ( or in this case that 1 inch long feed-through ) into the load panel without requiring splicing.Raco has boxes specifically made for this purpose. you terminate the MC in special push-in connectors. . your wire can then either be spliced , or fed through EMT to go on to where-ever. . Problem is i can;t find the damn things anywhere ...at 0:33 you see something similar to my setup. the loadbox is front , the cables come form the back of the wall. except, in my case the load center and the dugout box would be mounted back-to-back with a 1 inch pipe between them going through the wall. i cannot top mount since my loadbox is a solar approved one that needs the top opening to wire in the inverter before the main cutoff

author: Monkeh
author_rank: Super Contributor
timestamp: July 15, 2020, 10:59:12 pm
content: Quote from: free_electron on July 15, 2020, 10:40:50 pmThey were meant to come out in May, but, well, things have happened..The video demonstrates how you get your 3" conduit in. I'm not sure that box is tall enough to do that on the back cleanly, though. I also don't see any proper method for earthing it other than by the conduit..If your conduits are suitably spaced, a pair of the 8" GRAND SLAM(!!!) boxes would seem suitable (again earthing issue). SC080803NKSTRC for the plain rear with no knockouts, readily available.

author: MarkF
author_rank: Super Contributor
timestamp: July 16, 2020, 01:30:56 am
content: How many circuits are we talking about?You don't need the fancy RACO Dugout Box. Just a metal enclosure with standard knock-outs and bushings.Example:Box (a different form factor maybe better for you situation)https://www.lowes.com/pd/WIEGMANN-SC-Gray-Metal-Weatherproof-New-Work-Standard-Enclosure-Wall-Electrical-Box/50311355orhttps://www.homedepot.com/p/WIEGMANN-NEMA-3R-6-in-x-6-in-x-12-in-Carbon-Steel-Weatherproof-Wiring-Gutter-Wall-Mount-RSCG060612/303013817Bushinghttps://www.lowes.com/pd/Sigma-Electric-ProConnex-3-8-in-Set-Screw-Spacer-Flexible-Metal-Conduit-Compatible-Conduit-Fitting/3364750The issue I see is that the 3" conduit needs to be continuous between the outside load center and the inside distribution box.Ideally, without wire splices in the distribution box (i.e. the wires just go straight through to a breaker outside).I would recommend you go to your local Electrical and Lighting Distributor, tell them what you trying to do and ask what they recommend.Take pictures also. They can tell you what will meet code in your area.Be aware: do-it-yourself wiring may void your home insurance...

author: free_electron
author_rank: Super Contributor
timestamp: July 16, 2020, 02:09:13 am
content: 30 to 34 MC cables. i want every room on its own 15 amp fuse (i'm running 12/2 but fusing at 15 amps) led lights don't draw much1 master bedroom + bathroom on gfci2 office/lab1 guest bedroom1 dining1 living / tv area1 outdoor lights (wall sconces , door number , pathway lights )1 patio on gfc ( generic outlet + ceiling fan)1 barbeque island on gfi (fridge and utensils)3 kitchen ( toaster , other utensils )1 microwave1 refrigerator1 garbage disposal1 washing machine1 dishwasher1 oven1 cooktop1 venthood1 garage lights and door2 garage workshop 110v1 garage workshop 240v 30 amps2 car charger (240v) 8/3 30 amps each1 sprinkler and water treatment system1 garden tools (1 front , 1 back)the following are big cables ( aluminum ) and i will leave those in their own hole. not touching this1 dryer (240v)1 water boiler (240v)1 airconditioning (240v)These come in separately in another knockout from underground: not touching this1 poolpump (240v)1 saltwater cell pool + lightsThe wiring now is deplorable ...1 circuit for all the lights in bedrooms and hallway , 1 circuit for other lights2 kitchen circuits1 outdoor circuit1 garage circuit1 washer1 dryer1 oven / range ( i have split oven and range )1 garbage disposal.And yes, licensed electrician will do it , but i run the cables to save money...i can crawl in the attic and screw the cables down and place the junction boxes. he can strip the ends and tie them down.I'm just exploring options now. and see what is possible. Compared to europe , electrics in US is garbage. You can't even get nice wall switches like bTicino or Legrand. it's all uniform paddles or rockers from the 40's ... most outlets aren't even tamper proof. Such basic things are unthinkable in europe.

author: MarkF
author_rank: Super Contributor
timestamp: July 16, 2020, 03:05:55 am
content: Why are you running Metal Clad for general house wiring?Generally, MC cable is only for industrial applications. Not residential wiring.You really want one or two 200Amp breaker panels inside instead of having the breakers outside.Normally in the USA, only the meter is outside with heavy wiring to one or two Main Breaker Load Centers.You could add two breaker boxes inside (one large entrance wire through each 3" hole with only two large disconnect breakers outside).Here is an example of what a new install looks like up to the point of adding the breakers.

author: free_electron
author_rank: Super Contributor
timestamp: July 16, 2020, 04:48:10 am
content: i have experience with rodents ... my current place had damage due to squirrels getting in the attic. Some idiot decided that the outer sheeting of romex should be made from ... plants ... one morning i woke up , switched on the light and all went dark in the house... the electricians came out and found that every single wire in the attic had been stripped or at least bite marks on it. Total cost 6000$ ... not counting removing all insulation to find the nests , clean up the poo , before the electrical guys would touch it. which was another thousand, and then another thousand to put fresh insulation back in afterwards. and then the pest control guys, the roofing guys to find and plug the entrance ...fortunately the HOA had to cough it up ... as it was in common space. i am on the board. i saw the bills...So , now that i have a new place and am remodeling and have to open the drywalls anyway and install insulation in the attic... any wire that is NOT easily accessible or replaceable : MC. let them try to bite through that.Like i said : i am from europe : all electrical installations there are done in brick or cinderblock walls and it is all in pvc conduit or special cable that is directly embeddable in brick wall. we never have pest problems in the electrics. (by the way i am a licensed electrician in europe. i have done a number of installations including a 4 unit apartment. inspected, signed off without issues. i have done the trade school, so i'm not jack-the clown. i just need to find my way around the american system. i have a contractor that will do the wiring in the load box and get the permits and inspection done. he's ok with me running the actual cables point to point and terminate them in the junction boxes. he was happy i would do that part as i want a whole house automation system on Z-wave so every switch is intelligent and he has no experience with that. he gets to learn from me ..)So : since a roll of 250 ft MC 12/2 costs 139 $ ... and i need about 800 ft of it to run fresh wire from the load box the every room ,through the attic. So why not ? it is a one time cost of 500$ in material and i never will have to worry about rodents.Fuck that romex stuff. That is good for inside the drywalls. But in the attic ? metal clad please. ... you want to risk your house for 500$ in saving ?I am not moving the load panel. It is a new panel that was installed only 2 years ago when they upgraded the service to 200 amps and made it solar ready (mandatory in california now) . They fed the existing house wiring , from the garage, through two entrance nipples (2.5 inch ) , so i will go the same way. The holes are there, it is weathertight. Pull one cable out , plug one cable in ... easy to do. I am just looking for a clean way so i don't have to splice my MC onto something , to run it through the wall into the load box. The previous owner already made a mess of certain things by splicing bits of cable to form a long one. i want uninterrupted point to point runs.Moving the loadbox would be a nightmare as the feed to the house is overhead so the weatherhead comes through the roof directly into the load box.i asked the power company if they could give me an underground cable to get rid of that unsightly pole .. 20.000 $ .. yikes. if i move that loadbox it would cost me lots of money since they would be involved running a new house line as well ...So moving the box is out of the question.Right now they are feeding romex into it from the drywall cavity, through the two nipples.. all i need is a box that can terminate MC so i can run the unsheathed wires through the two nipples , just like that raco solution. The local home depot and lowes don't have really anything i like ( in the sense it doesn't have enough knockouts , or space to work in. that dugout box is ideal.I'll go talk to the local electric supply store tomorrow , see what they have. it's weird that Square-D ( who makes the load box, does not have something for that purpose... )

author: Gregg
author_rank: Super Contributor
timestamp: July 16, 2020, 04:38:17 pm
content: You can buy electrical gutter in many sizes and use a punch or hole saw to place the in and out MC and 3" conduit wherever you want. Also there are plain junction boxes available without knockouts that would be suitable. You certainly do not need anything fancy unless the cost of the fancy box is justified by labor savings in bulk installations. Properly installed wire nuts are suitable for connections inside the junction box and a ground strip to connect all of the grounds together will save space and time. A neutral bus insulated from the enclosure may be appropriate if there are no GFI or arc flash breakers in the distribution panel.I haven't looked at recent NEC rules, but there used to be a 2 foot tap rule that allowed you to stuff a lot of circuits into a short connector conduit without de-rating the current capabilities. If your 3" conduit is longer than 2 feet, you may want to consider multiple smaller conduits in parallel.Edit: If you want to make it neat and tidy looking, you could use DIN rail mounted terminals. Be sure to label your connections for future trouble shooting or changes.

author: Monkeh
author_rank: Super Contributor
timestamp: July 16, 2020, 04:46:23 pm
content: Quote from: Gregg on July 16, 2020, 04:38:17 pmThat's just nasty. Let's complicate testing by terminating the circuit in multiple locations..

author: free_electron
author_rank: Super Contributor
timestamp: July 16, 2020, 05:56:17 pm
content: the conduit is 1 inch longit is only used as a pass-thru from the wall cavity , through the stucco into the load box.so no derating issues there.absolutely no wire splicing in boxes !. i want uninterrupted runs from loadbox to room, or point of load (kitchen appliances , oven , cooktop, water boiler , airco etc all will be continuous runs ). the bedrooms will have a continuous run to the room and then split out to various power outlets and light fixtures.messing with electrical gutter is no-go. i have too many cables.That raco thing is the perfect solution. if only it were available. i tried finding some other companies that make similar but they are all with like 6 knockouts max ... i need way more than that. i might have to put 4 or five of those next to one another and 'daisy chain' stuff. but that's ugly and looks non professional.

author: themadhippy
author_rank: Super Contributor
timestamp: July 16, 2020, 06:05:32 pm
content: QuoteIn the uk we have these wonderful things called holesaws ,we use them to cut holes in things like trunking so we can terminate a gland. If i was doing this i would put a lump of 6" trunking on the wall with the 3" conduit entering the rear of the trunking,either with a suitable bush,or gromit strip and paxolin,and terminate the 34 steel cables into the trunking

author: free_electron
author_rank: Super Contributor
timestamp: July 16, 2020, 06:17:38 pm
content: Quote from: themadhippy on July 16, 2020, 06:05:32 pmtoo much work ...but, it looks like we have a solution. !https://www.homedepot.com/p/WIEGMANN-NEMA-1-4-in-x-4-in-x-24-in-Screw-Cover-Wireway-S4424RC/202097235A screw-cover wireway. These are avaialble in any length , and come with knockouts. terminate MC in the appropriate plug-in , press into knockout , bundle the wires and feed through another knockout through the wall. !With this kind of stuff it's always the problem to know the right terminology. This is called a wireway with knockouts. You mention that and they immediately know what you are talking about.You try to describe it as a box to bring in a bunch of MC cable and then feed the wires into a loadbox .. and you get blank stares ..Ask in the store for a double power outlet and you get blank stare. ask for a wall socket and they throw them at you ...

author: Monkeh
author_rank: Super Contributor
timestamp: July 16, 2020, 06:24:46 pm
content: And to everyone else, that's called an overpriced piece of trunking with a handful of knockouts presented.It really doesn't take that long to pilot drill and punch holes in a piece of trunking.

author: SeanB
author_rank: Super Contributor
timestamp: July 16, 2020, 06:32:55 pm
content: Still think though that the Electron wants to avoid the drilling of close to a hundred holes in shitty electrogalvanised metal, and wants to get it ready to use. If you have the choice of having to remove hundreds of small shavings of metal, where they can cause shorts, or just knock out a few ready to use holes as needed, and not have to worry about slivers falling into the US preferred open wire clamps and being ground into your cable. Better wife factor, as it likely will be a lot faster, and lower noise than drilling, and the holes at least will all be in a row.

author: free_electron
author_rank: Super Contributor
timestamp: July 16, 2020, 06:44:10 pm
content: Quote from: SeanB on July 16, 2020, 06:32:55 pmExactly. plus you can't just use any kind of trunking. It needs to be rated and approved for purpose. this piece is made for that purpose : terminate MC or other cable ( using appropriate feedthru's ) and bundle the now loose wires to feed them into either a metallic pipe or into a loadpanel. Code compliant, type rated and approved. And that's what i want. There are rules as to how close cable entries are allowed to be. And how many wires per diameter. This fits all requirements.

author: Monkeh
author_rank: Super Contributor
timestamp: July 16, 2020, 09:31:29 pm
content: And one of those wireways, at 60" long (!) still only has 32 knockouts for your 34 circuits, although I count 28. Some of those knockouts are 3/4", some are 1" (okay, some are 3/4-1", but that's balls because the larger diameter might come loose), some are 1 1/4", so you'll have to have different fittings or adapters to suit all the holes. Sounds like a dogs breakfast by the time it's all done. If that's correct, I'd proceed to do it wrong.

author: themadhippy
author_rank: Super Contributor
timestamp: July 16, 2020, 09:43:49 pm
content: QuoteAll that for safety but you can still use wire nuts

author: Monkeh
author_rank: Super Contributor
timestamp: July 16, 2020, 09:49:07 pm
content: Quote from: themadhippy on July 16, 2020, 09:43:49 pmAll that for selling overpriced assemblies rather than having tradesmen fabricate things. Transferring the profit to the two or three companies actually making products under a few dozen names.

author: Gregg
author_rank: Super Contributor
timestamp: July 17, 2020, 04:09:14 am
content: A professional electrician would use an appropriate length of gutter and a chassis punch to make the junction box you want. Gutter is available in many sizes and lengths with end caps and covers to suit; they are approved for the purpose you propose. The punched holes only have to be far enough apart to allow the lock nuts on the fittings to be tightened.Enclosed picture of a power distribution unit in a data center in San Jose shows the whole bottom with close knockouts and ground busses near the knockouts so that the wiring to the breakers is less congested.I could have punched 32 holes in a length of gutter in about an hour. If punched or drilled before it is installed it is very easy to remove any metal chips.

author: free_electron
author_rank: Super Contributor
timestamp: July 17, 2020, 03:15:02 pm
content: Quote from: Gregg on July 17, 2020, 04:09:14 ammaybe i'll go that way then. i am using press-fit anyway. no need for lock nuts.

author: Monkeh
author_rank: Super Contributor
timestamp: July 17, 2020, 03:25:40 pm
content: Quote from: free_electron on July 17, 2020, 03:15:02 pmThe fitting has to be secured into the box..The trouble with gutters is they're not designed for this orientation. But a simple piece of trunking (someone translate that to American for me.. trough?) is.

author: Gregg
author_rank: Super Contributor
timestamp: July 17, 2020, 08:11:42 pm
content: Quote from: Monkeh on July 17, 2020, 03:25:40 pmHere an electrical gutter [also called a wireway] is merely 3 sides of a metal box that can be cut to length if a standard length isn't what is needed. End caps and covers are separate. some are available with partial punched knockouts but usually they are concentric sizes and not where always wanted. It is within the rules of the NEC to make connections inside a gutter.Enclosed picture shows an industrial installation of a long gutter over distribution panels. This method is extremely useful when additional wiring may be required to connect circuits to a live panel as most of the wiring can be safely done to the gutter ahead of the final connection.

author: Monkeh
author_rank: Super Contributor
timestamp: July 17, 2020, 08:42:41 pm
content: Quote from: Gregg on July 17, 2020, 08:11:42 pmEhh, trying this post again for about the third time.. The naming convention and earlier example of a 'gutter' from Home Depot is.. very confusing to the entirety of the rest of the planet. That's trunking. Great - plain old open ended trunking is exactly fine here.Apologies for going off-topic, but it's easier to learn Klingon. The prior example looked like the top comes off at first glance, which is obviously not suited (and, y'know, makes more sense of a product called a 'gutter'), and although at second examination it appears it doesn't I wouldn't trust it for continuity (assuming your code even cares about that here).