This disconnect is used to supply a large trash compactor in an alley where public access is possible between a hotel and a market!

The cover is nicely padlocked. What a pity somebody didn't apply the same zeal to the rest of the unit. I hope the panel is securely grounded for when one of conductors finally contacts the metal when the insulation wears through.

Unsecured cables, missing or damaged protective seals or grommets, improperly tightened glands etc. seem to be a worldwide problem.

This is a good image showing that concentric knockouts and flexible raceways or cables should not be considered a compatible arrangement... Sheet-metal reducing washers are also very marginal/of potentially unacceptably high impedance for equipment-grounding integrity to the metallic connector. In my book, suitably-threaded reducing bushings and a pair of locknuts are far more desirable.

OK, I have to type this.....
As it appears the cord is aiming "down", along with that gravity thing.....why wouldn't you exit the disc at the bottom??

Is this outside? that doesn't look like a suitable strain relief.

John

The pictured cord connector is a kellems-type grip. That should be a good application sans the KO donuts.






[This message has been edited by Bjarney (edited 10-03-2003).]

My personal feeling is that equipment should not come with concentric knockouts.

The company I work for orders all panel tubs, troughs and cans with no knock outs.

If your an electrician you should have the tools to make the holes the right size and where you need them.

This picture is a perfect example of why, if I was forced to use for this rubber cord I would install reducing washers over the entire concentric KO.

Now why is there rubber cord hanging from this disconnect anyway. 400.8(1)

Hi Guys: I have a couple of questions about this. Since using the concentric KO's for this type of application is obviously not suitable, and if for some reason it is not possible (or desirable...?) to exit from the bottom of the enclosure, Would there be anything wrong with using a KO punch to set one properly sized hole above the concentric?

Is a kellems grip suitable for use outdoors like this - I'm assuming this is an outdoor install bacause of the 3R disco?

Mike (mamills)

I'm assuming the rubber cable (SO, as we call it here) can be explained as the supply cable that came with the equipment (the trash compactor). I've seen these type of hook-ups on some very large compactor units installed behind huge movie houses in California, Idaho, and Texas. I've always assumed this installation was acceptable only because these compactor units were installed in their own masonry-block enclosures (they all passed inspection).
If, however, this particular installation is within a public traffic area, I would certainly think protective conduit would be required.

Also, even if this connector were installed properly, what about water intrusion? This is a wet location, is it not?

mamills — The pictured style of mesh/basket grip may only be rated dusttight and not rain- or watertight. See page 67 of: www.hubbell-wiring.com/library/SectionT-part1.pdf

BTW—equipment manufacturers hate concentric KOs for a different reason—their punches and dies to stamp that pattern in sheet metal are a constant headache in terms of maintenance—they are hard to keep sharp. I agree than “NOKO” cans and wireways make for a much neater installation, and generally improve raceway grounding continuity. Some consider installation of offset nipples or connectors “tacky,” and not the mark of a true electrician.

The matter of KO location in 3R disconnect switches/enclosures is a salient one. As I see it,
99NEC430-91 Motor Controller Enclosure Types discuses the issue, but article 430 only indirectly covers disconnect switches and not “pull cans” containing circuit conductors which may be exposed/live with the cover removed, or insulated to a “600-volt” degree. I have an impression of what should be addressed, but cannot provide a specific reference in a ‘code-like’ publication or standard. There are bits and pieces on “Enclosure Types” at places like: www.hoffmanonline.com/PDFCatalog/SpecifiersGuide/ChAp6_7.pdf

In case of the pictured disconnect, you could interpret that factory-provided KOs are permitted when any part of their opening is below exposed energized parts within the enclosure. Any opening that encroaches on live parts would generally require the equivalent of a gasketed hub, if I interpret that correctly. Yes or no?

Zapped if we go with the assumption that this feeds a trash compactor pump (or any equipment) and you want to use a flexible cord ,the closest article that would allow this would be 400.7(A)(6), but in order to be able to say it is for frequent interchange it needs to have an outlet and plug.

If you have to unwire the cord to change the equipment you could just as easily unwire a piece of LFMC.



But with the cord hardwired into the disconnect IMO it is a violation of 400.8(1) and (4)



Bjarney

I have no doubt that concentric knockouts are a headache for the manufactures, set the dies to tight and the KOs will fall out, let them get to loose and the KOs are no more than an outline of the KOs that are not removable with a sledge hammer.

I think a big problem with premade KOs is that they often end up half way in the way, so when you punch a hole where you want you end up with a hole resembling an 8.

Bob

[This message has been edited by iwire (edited 10-04-2003).]

Code-accepted or not, one alternative substitute to a receptacle and male cap on SO cord is a female connector body on the SO-cord opposite end mated with a locking-style ‘flanged inlet’ or ‘motor flange’ mounted on the utilization equipment.
 
http://www.hubbellcatalog.com/wiring/section-b-datasheet.asp?FAM=Locking_Devices&PN =HBL2515




[This message has been edited by Bjarney (edited 10-04-2003).]

Yeah, but typically you won't have a fixed cord with a female connector but an extension cord. That practice is pretty common for European garden appliances and larger 3ph stuff like table saws, etc.

Here is the rest of the story!!

I have never seen these units installed correctly, and that pump, tank and control box never gets bolted down.

So how about it Joe, would you approve flexible cord for this installation?

iwire:

If I was asked to inspect this type of installation I would want to find out if the unit came with a cord cap, or if it was designed to be connected as shown.

I see were the entry was in the bottom at one time, and I will bet that some vandals pulled, or bent the fitting at the end to break the concentric out?

If an electrician was to use conduit or EMT it would not be difficult to terminate into a box, and receptacle that would be a better method like BJ suggested above.

It's been this way for as long as I have been in Boston, going on 25 years!

Joe

I think the OD-green cord ends are usually called ‘MS connectors.' [mil-std] Their very limited internal creep and strike dimensions {clearances} usually make them an awful choice for any outside AC-power or –control circuits.

Bjarney, Those are supply and return hydraulic lines with quick connects.

There is no electrical in the "big box" all electrics are mounted to the tank pump combo.

These units are a sore spot with me, our plans will call for a disconnect located outside for a trash compactor, then a non-electrician will come and "install"his pump unit without any concern for the NEC.

This one is a basic install but some are much more elaborate with the pump unit outside but a set of controls placed inside the building near the trash chute.

The common wiring method will be flexible cord or LTFM supported with a few tie wraps often with a hydraulic line for a pressure gage tie wrapped to that.

I would like to have inspectors shoot these down but often it is done after our final.

Oops, iwire — I screwed up big time. I used to have to deal with those at 480V, and the reason was that they were cheap compared to pin-and-sleeve connectors.

Regarding iwires point several posts back about 400.7(A)(6) not being correctly applied, I was wondering if 400.7(A)(7) "Prevention of the transmission of noise or vibration" applies?

On the (very few) compactor installations that I've seen, there is invariably some form of weatherproof flexible whip between the disconnect and the pump enclosure.

-Jon

Nice looking lug that the white wire terminates at in the disco.

wow that some really quaility work there
nice grounding also