• We will be performing upgrades on the forums and server over the weekend. The forums may be unavailable multiple times for up to an hour each. Thank you for your patience and understanding as we work to make the forums even better.

Proper coupler from 1/2" EMT to 3/8" FMC?

Merry Christmas
P

pfus

Member
Location
Chicago NW burbs
Occupation
Elect. Engineer
LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
It's confusing because it has contradicting info:

"For Use With FMC/EMT Conduit"

"Used to join 1/2" EMT and up to two 14/2 and 12/2 Romex, Non-Metallic Cables."

There are others that leave no doubt:

1732892599166.jpeg 1732892639307.jpeg 1732892621990.jpeg
 
infinity

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
P

pfus

Member
Location
Chicago NW burbs
Occupation
Elect. Engineer
G

garbo

Senior Member
pfus said:
There are several products that look like this:
www.butlersupply.com

Bridgeport® 280-DC Combination Coupling, 1/2 to 3/8 Inch EMT, Zinc Die Cast

Bridgeport® 280-DC Conduit Combination Coupling With 2-Way Phillips/Slotted Head Screw, 1/2 to 3/8 in, For Use With FMC/EMT Conduit, Die Cast Zinc, Ball Burnished
www.butlersupply.com www.butlersupply.com
But almost look like a NM clamp.

Vs.


Is the first type really an acceptable method to connect 3/8" FMC?
Click to expand...
I clicked onto the site and it appears the Bridgeport fitting is for 1/2" EMT to one or two 14/2 or 12/2 NM cables.
 
G

garbo

Senior Member
Just curious , it only took me 35 years to find out that you are not allowed to make a home made transition fitting using a RMC coupling. Found thus out at one of the first great local IAEI meetings I attended. So being its way easier to stock RMC coupling do many sparkies still make the transition from say EMT to AC or MC cable? Made countless ones up wrench tight and never had one cone loose. The two companies that I worked for did not want to bother stocking countless transition fittings.
 
W

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
JohnE said:
What transition did you make that is prohibited?
Click to expand...
Take two standard connectors (intended for holes in boxes), and join them with an RMC coupler.

This appears to fit together and create a transition coupling, but isn't an evaluated use for the components.

IMHO this very likely creates a perfectly suitable transition, but since it hasn't actually been evaluated....

Jonathan
 
JohnE

JohnE

Senior Member
Location
Milford, MA
winnie said:
Take two standard connectors (intended for holes in boxes), and join them with an RMC coupler.

This appears to fit together and create a transition coupling, but isn't an evaluated use for the components.

IMHO this very likely creates a perfectly suitable transition, but since it hasn't actually been evaluated....

Jonathan
Click to expand...
I'm just not understanding what code or standard this violates.
 
JohnE

JohnE

Senior Member
Location
Milford, MA
LarryFine said:
Couplings are made for joining conduits, not fittings.

Fittings are made for KOs and locknuts, not couplings.
Click to expand...
So what, exactly, would you fail the job for? (And while I haven't been on here much lately, I greatly respect your opinion, Larry)

MA does have some amendments that may not apply nation-wide....
 
LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
JohnE said:
So what, exactly, would you fail the job for?
Click to expand...
Fittings are supposed to be used in accordance with their listings and instructions.

This is kind of an exception to the what-isn't-prohibited-is-allowed generalization.

JohnE said:
(And while I haven't been on here much lately, I greatly respect your opinion, Larry)
Click to expand...
1733004508366.jpeg
 
JohnE

JohnE

Senior Member
Location
Milford, MA
In MA, the amendments to the NEC state:

90.4 Enforcement. This Code shall be used by the authority enforcing the Code and exercising legal jurisdiction over electrical installations. The authority having jurisdiction of enforcement of the Code shall accept listed and labeled equipment or materials where used or installed in accordance with instructions included with the listing and labeling. The authority shall have the responsibility for deciding upon the approval of unlisted or unlabeled equipment and materials, and for granting the special permission contemplated in a number of the rules.

I realize this forum is based on NEC primarily. But given this article, I can see the argument to allow the installation in OP, at least here in MA.

But MA is a separate discussion, I realize that. I do recognize and appreciate the "permissive code - what is isn't prohibited is allowed". I had a lot of difficulty when my day job changed to enforcing MA Zoning, which is entirely opposite - if it isn't allowed expressly, it is prohibited....but I digress...
 
fishin' electrician

fishin' electrician

Senior Member
Location
Connecticut
Often, what is 'not allowed', is just stupid.
winnie said:
This appears to fit together and create a transition coupling, but isn't an evaluated use for the components.

IMHO this very likely creates a perfectly suitable transition, but since it hasn't actually been evaluated....

Jonathan
Click to expand...

I have been evaluating connector/rigid coupling/connector for over thirty years. Works just fine. :cool:
 
Knuckle Dragger

Knuckle Dragger

Master Electrician Electrical Contractor 01752
Location
Marlborough, Massachusetts USA
Occupation
Electrical Contractor
garbo said:
Just curious , it only took me 35 years to find out that you are not allowed to make a home made transition fitting using a RMC coupling. Found thus out at one of the first great local IAEI meetings I attended. So being its way easier to stock RMC coupling do many sparkies still make the transition from say EMT to AC or MC cable? Made countless ones up wrench tight and never had one cone loose. The two companies that I worked for did not want to bother stocking countless transition fittings.
Click to expand...
I am guilty of doing this countless times when I didn't have a transition fitting. I never was called on it or realize it wasn't permitted unit i read it on this forum.
 
W

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
The paper that @infinity links is spot on about why it is plausible that such home made transition fittings might not work properly...buy I'd lay money (not much :) :) ) on my claim in post #10. Rephrased: 'They probably work just fine but have not been evaluated to demonstrate that they work just fine.'

My guess is that an officially evaluated component to allow home made transition fittings would have something that looks like a conduit coupling, but with straight threads, and possibly special locknuts to firmly bind the connector to the coupler.

Maybe there is a market?
 
qcroanoke

qcroanoke

Sometimes I don't know if I'm the boxer or the bag
Location
Roanoke, VA.
Occupation
Sorta retired........
winnie said:
The paper that @infinity links is spot on about why it is plausible that such home made transition fittings might not work properly...buy I'd lay money (not much :) :) ) on my claim in post #10. Rephrased: 'They probably work just fine but have not been evaluated to demonstrate that they work just fine.'

My guess is that an officially evaluated component to allow home made transition fittings would have something that looks like a conduit coupling, but with straight threads, and possibly special locknuts to firmly bind the connector to the coupler.

Maybe there is a market?
Click to expand...
There are transition fittings that are approved.
We just use a box to transition from one to the other.
We were rejected for it in a few buildings for using the connector coupling connector setup.
And they were a long ways away from our factory so it cost us quite a bit to fix it.
We don't do that anymore.
 
You must log in or register to reply here.
Top