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#83725 - 02/17/03 01:34 PM bushings don`t fit well  
Reel-Break  Offline
Member
Joined: Apr 2002
Posts: 178
nc
I`m kinda fustrated running some EMT this weekend and on most of the male adapters the bushings would not tighten as they should.And yes I tightened the lock nut tight.Any one else share this situation.Can you use the metal bushings w the insulator without the locknut?I might look for some thin locknuts.Everytime I pull on the wire the bushing falls off.Just one of those days.The brand of adapters was Keer 3/4"male adapters.


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#83726 - 02/17/03 03:12 PM Re: bushings don`t fit well  
Reel-Break  Offline
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Joined: Apr 2002
Posts: 178
nc
I left out one very important detail the boxes were regular raco 4x4 and 2x4 boxes all standard thickness.


#83727 - 02/17/03 05:09 PM Re: bushings don`t fit well  
CDN_ELECTRICIAN  Offline
Member
Joined: Jan 2003
Posts: 73
Concord,Ontario,Canada
Have had the same problem, especially with the smaller size EMT, 1/2"& 3/4".

Problem is the threaded portion is too short for both the lock nut supplied and a bushing.

There fore here is how we deal with it:

1- go through the junk box and find smaller lock nuts. IE. leftovers from BX connectors.

2- use insulated throat connectors (little more $$$ but factor in time lost, bushings falling off, looking for lock nut....

3- use metal bushing, depending on manufacturer, may be long enough to use as both lock nut and bushing.

My choice is "Insulated Throat" connectors, best $ saver in long run.


#83728 - 02/17/03 05:25 PM Re: bushings don`t fit well  
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
This is a problem in large sizes too, and the best idea is the insulated throat type as CDN said.
Or look at them before you install them if you think they are short ask for a different brand, some steel connectors have long threads.


Bob Badger
Construction & Maintenance Electrician
Massachusetts

#83729 - 02/17/03 09:39 PM Re: bushings don`t fit well  
electure  Offline


Member
Joined: Dec 2000
Posts: 4,260
Fullerton, CA USA
Is there a reason you were using bushings on the EMT connectors?


#83730 - 02/18/03 12:28 AM Re: bushings don`t fit well  
frenchelectrican  Offline
Member
Joined: Feb 2003
Posts: 939
Wi/ Paris France { France for ...
yes there is a reason to use the bushing due prevent wire damage and by nec codes i cant remebber which section say but anything over 250 volts from line to ground must use insluatited throut. it is very common on 277/480 networks but can use on lower voltages too if deal with very deep box i use the bushing too. i am sure few other memebers can help you with this and what cdn say that one idea it work with him i use the same way and i do check the suppliers to see what they have sometime i swap few diffrent way to deal with it

merci marc


Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)


#83731 - 02/18/03 01:44 AM Re: bushings don`t fit well  
Len_B  Offline
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Joined: Jan 2003
Posts: 53
New Hampshire
Typically, bushings are not required on manufactured fittings with conductors under 600v to ground. I believe the requirement for using insulated bushings on manufactured fittings is in Art 300, and requires the use of a bushing (or fitting with an insulated throat) when ungrounded conductors of #4awg or larger are present. Insulated bushings are, of course, always required on threaded conduits of any size.

The over 250 volts to ground reference is, I believe, from Art 250 for bonding of systems over 250v to ground, requiring the use of grounding bushings and/or locknuts, etc.

Len


#83732 - 02/18/03 08:49 AM Re: bushings don`t fit well  
electure  Offline


Member
Joined: Dec 2000
Posts: 4,260
Fullerton, CA USA
Len,
Exactly.
(Also,The bonding [bushing] requirement in Article 250.97 for over 250V to ground only applies to oversize, concentric, or eccentric KOs on boxes or enclosures not listed for the purpose)...S


#83733 - 02/18/03 09:59 AM Re: bushings don`t fit well  
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
This problem is a bigger headache when it is bonding bushings, not enough threads to run the screw down into.

Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts

#83734 - 02/19/03 01:09 AM Re: bushings don`t fit well  
frenchelectrican  Offline
Member
Joined: Feb 2003
Posts: 939
Wi/ Paris France { France for ...
indeed iwire;

yes that is the other good point about that one with bonding bushing and many time it is thicker than the standard bushing and it do come with set screw with it and some case i have to swear at it because i got red tagged before with that one ..

unfortealy i have to be more carefull with the number of thread length wise so i can able to put the k.o. bushing then bonding bushing on it it is ok with ridge pipe with extra thread there but not always the case with emt fitting

merci marc


Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)



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