NEMA 4X

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wireday

Senior Member
Location
New England
Occupation
Master electrician
I have a damp/wet/splash type area, Is NEMA 4X with gaskets, any different Then 3R boxes when it comes to safety? My thought (which may be wrong) is if a box is properly grounded NEMA 4X or 3R comes down to equipment damage, and preventing water damage to apparatus inside the enclosure. If the NEMA 4X or 3R box was wet inside and out would safety or shock hazard be any different? Seems if everything is properly grounded/bonded it would not pose a shock hazard,just damage to apparatus inside the box.
 

Ken_S

Senior Member
Location
NJ
Occupation
Electrician
Personally I would install the proper enclosure for the environment.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
There is no real difference in water damage to contents of type 4 or type 3r boxes. The issue is that type 3r boxes allow water inside but you have to locate things inside it so they don't get wet and water can drain out of the box.

Type 4x boxes don't allow water into the box in the first place.
 

kwired

Electron manager
Location
NE Nebraska
We have many 4X enclosures installed on or jobs, water entry isn't an issue, however condensation is.
Yep. Drill drain holes in it and technically it is now 3R.

Some N4 enclosures will even have screws in the bottom and instructions to remove them to create drain holes and changes it to 3R, or will have instructions to drill holes in the bottom to change to 3R.
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
There are devices you can install into the bottom of a Type 4 / 4X box called a “breather/drain” that maintains the Type 4 rating.

The “X” by the way is for corrosion resistance at a lever much much higher than that required of Type 3R. It shouldn’t be taken lightly when specified.
 

wireday

Senior Member
Location
New England
Occupation
Master electrician
There is no real difference in water damage to contents of type 4 or type 3r boxes. The issue is that type 3r boxes allow water inside but you have to locate things inside it so they don't get wet and water can drain out of the box.

Type 4x boxes don't allow water into the box in the first place.
I need to knock out for LFMC on 4X boxes, how do I make that 4X compatible? Is a simple LFMC connector with seal ring 4X?do I need Myer hub, is a Myer hub locknut a ground with a metal box?
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I need to knock out for LFMC on 4X boxes, how do I make that 4X compatible? Is a simple LFMC connector with seal ring 4X?do I need Myer hub, is a Myer hub locknut a ground with a metal box?
The instructions that come with it will tell you the rating of the fitting.
 

kwired

Electron manager
Location
NE Nebraska
There are devices you can install into the bottom of a Type 4 / 4X box called a “breather/drain” that maintains the Type 4 rating.

The “X” by the way is for corrosion resistance at a lever much much higher than that required of Type 3R. It shouldn’t be taken lightly when specified.
It isn't taken lightly in the checkbook when your 4X option is to go with stainless over mild steel. ;)
 

Eddie702

Licensed Electrician
Location
Western Massachusetts
Occupation
Electrician
@wireday you have to either use a hole saw for KOs or even if you use a KO punch you have to run your drill at the lowest possible speed or the stainless will ruin your drill bits no matter what kind of drill bits you by
 

kwired

Electron manager
Location
NE Nebraska
I need to knock out for LFMC on 4X boxes, how do I make that 4X compatible? Is a simple LFMC connector with seal ring 4X?do I need Myer hub, is a Myer hub locknut a ground with a metal box?
Standard LFMC fitting should be rated N4. To get 4X rating probably needs to be stainless fitting or other more corrosion resistant material.

Myers hubs should be listed for grounding/bonding as a general rule. There are some with a lug on the locknut for cases where there maybe is an impaired connection situation.
 
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