Wall pass-through electrical cabling

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Old 05-31-18, 12:54 PM
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Wall pass-through electrical cabling

So I have a situation that I want to do the easy way, but it might not be code...

We have some hot and loud vacuum pump equipment on one side of a wall that has a pass-through to connect vacuum lines to equipment on the other side.

This equipment on the other side of the wall is very delicate electronic testing devices that also need to be temperature controlled.

We purchased some very large battery backup (6kVA) units that require 220v at 30a wall plugs, which we have already. This equipment is to connect to both the pumps and the electronic testing equipment. The pumps are 220v as well as the main test equipment, there are also two 120v connections to computers and other test equipment to attach to the battery (has dual voltage outputs).

The problem is we want the batteries in the pump room. So we need to pass through the wall; one 220v line and two 120v lines (these two lines are actually attached to heavy-duty 8 plug surges). I am not sure if we can just put some 3" conduit (similar to what we are doing for the vacuum lines) to pass through the wall or we need some wall boxes and fab up a bunch of cables.

The room equipment room is closed and has a balanced AC setup (not pressurized) but we have a drop ceiling and plenum area above. The pump room is open with a standard pressurized AC system.

Any help would be great to get it done ourselves.
 
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Old 05-31-18, 03:53 PM
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What is your question? Had to use more spaces.
 
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Old 05-31-18, 04:34 PM
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NEC prohibits cords run through holes in walls. Best to talk with whomever handles your OSHA and other safety issues.
 
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Old 06-01-18, 09:36 AM
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Thanks for the answer Astuff,

That is exactly what I thought was the case. Others here were pushing the easy way, including our safety officer. We have a couple of places where they have done this (prior to my coming on board last year) and according to the "safety officer" - "well the fire inspections don't flag it, so it has to be ok." Um, yeah, no. Let's not go there with the other code violations I have already yelled, screamed and jumped up and down about...
 
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Old 06-01-18, 09:43 AM
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One more Question Astuff; would you happen to know the NEC code so I can give it to management? I couldn't actually find anything specific with the google, hence asking here. Otherwise, I would need to ask the safety officers (who is also the operations manager) buddy who is some type of "electrician" and I use that term loosely as some of the things he has done here are dangers waiting to happen...

Thanks again!
 
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Old 06-01-18, 01:01 PM
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Every once in a while you get a new safety inspector. Had one come from the insurance company and didn't like the power strips in the phone room on the wall board. They had been there in plain sight for about 20 years but suddenly had to be removed. Replaced with MC stapled to wall with 4x4 boxes and passed.

NEC ARTICLE 400 - Flexible Cords and Cables
400.8 Uses Not Permitted.

(1) As a substitute for the fixed wiring of a structure
(2) Where run through holes in walls, structural ceilings,
suspended ceilings, dropped ceilings, or floors
(3) Where run through doorways, windows, or similar
openings
(4) Where attached to building surfaces
(5) Where concealed by walls, floors, or ceilings or located
above suspended or dropped ceilings
(6) Where installed in raceways, except as otherwise permitted
in this Code
(7) Where subject to physical damage
 
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Old 06-01-18, 06:56 PM
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I would recommend installing inlets in the pump room that you could plug cords off the UPS into and then feed off the inlets to permanent wiring (MC cable or conduit) to the locations needed in the other room.
 
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Old 06-04-18, 09:45 AM
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Great thanks AStuff and Tolyn!

The number of visibly dangling power strips or daisy-chained strips was astonishing. And never flagged...

So could we use the MC (in A\V and IT we call these cable whips, though sometimes these are flexible plastic), with fabricated plugs, directly plugged into the UPS and run that through the wall to a breakout box on the other side? Or in this case, would that also considered a flexible line? I like to minimize the number of connectors in the path out of habit. Literally, the breakout box would be two standard 2 gang in-walls on the other side of the wall, no runs are needed to get to their destinations beyond getting through the wall. Or would we run the whip into a box on the pump room side that jumpers to hardline over to the breakout box on the other side?
 
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Old 06-04-18, 09:49 AM
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Might have my answer in the description for the MC

"It is UL Classified for Through-Wall Penetrations and is RoHS Compliant"
 
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Old 06-04-18, 11:16 AM
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Are these battery back up units UPSís and are supplied by 30 Amp 240 volts cord connected to wall outlets ? From the load side of these backup units you are connecting to 8 plug surges, (what are they?) just trying to understand what you have but I like Tolynís suggestion, the Inlets could be surfaced mounted and piped over the wall to the location in the other room where the other equipment would be plugged in using the proper receptacles.
Geo
 
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Old 06-04-18, 01:36 PM
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Geo

Yes, UPS wall supply is 30amp @ 208 nomial input.
The UPS has a split output that is stiffened and managed to 230v and 120v
230v goes to the pumps (two on this machine) and a large test machine, so three total outputs.
One power strip drives a computer system, monitor, printer etc, 5 receptacles total used.
One power strip is for another instrument that requires 120v, it takes 7 plugs.

The way I read the MC is for wall penetration:
Fabricate plugs on the MC to create a whip that can penetrate the wall on the pump side
Run the MC through the wall into a metal gang box mounted on the other side of the wall with receptacles for the equipment.
This way I would be running three MC whips into the wall for each required input.
Maybe use some type of metal trim ring to help support the penetrations.

If not the case:
Fab three male-male cables to be plugged into the UPS and plugged into receptacles in the pump room.
Run MC from that gang box to another gang box in the instrument room.
Connect instruments to that box.
 
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Old 06-04-18, 03:54 PM
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WHAT is a male to male cable? I hope you are not talking about a Suicde cable ! What is a stiffened UPS output? not trying to be difficult but I have never heard the term. Is this wall a standard 2X4 wall, if you don't like the idea of pipe how about 4" Sq's with inlet type receptacles plug the UPS output into theses and connect to boxes on the other side of the wall using short pieces of EMT and connectors, boxes would essentially be back to back, MC through holes in the wall is a bit of a Hack job IMO.
Geo
 
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Old 06-04-18, 04:16 PM
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Do not fabricate male-to-male cables. Please. In IT work, M-M is okay because it's low-voltage (extremely low amp, also) signal cable. In electrical supply, it is the kind of thing that gives electricians nightmares. It can literally kill people.
 
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Old 06-04-18, 08:06 PM
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WHAT is a male to male cable? I hope you are not talking about a Suicde cable
This is why I recommended inlets. No suicde cord needed. Also you cannot install cord caps on MC cable.

Example of inlet: https://www.amazon.com/Leviton-5278-.../dp/B003ATXIBG
 
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Old 06-05-18, 05:41 PM
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Yeah, Tonyn those are a much better idea if I can't cap an MC.

The UPS won't be moved once installed, but the use of MC I have seen connected to other equipment is a direct wire, so that makes sense. Just trying to fabricate as little as possible, oh well.

Never heard the term suicide cable, but it totally makes sense to not do that, thanks for bringing that up. Glad I asked that question! In IT and AV this is not a big deal like 8N1 says.

Geo, so this UPS has a "step-up" transformer to bring the wall 208v up to 230v output for the equipment. This also acts as an isolator take noise out (<3% THD) of the line and keep it metered at 230v plus/minus 3% under load. The term I always heard was a power stiffener, maybe an old term. What you suggested with the wall boxes was my original idea, was just trying to do this easier if possible even if a bit of a hack job. I have six to do now with three more coming.
 
 

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