J-Boxes

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gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
Are you using something like SAE's FB4, or one of their terminal cabinets?
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Does NEC 110.26(3) apply to a j-box with terminal blocks inside?

just where working space is required and where it is not required is pretty vague. People might argue that terminals would not be "likely to require examination, adjustment, servicing, or maintenance while energized". However, I can't tell you how many times I have taken a meter to a live terminal block while debugging something.

I think there is kind of a consensus among electricians that terminal boxes don't require working space, but the code is not completely clear about this. The thing is that it is pretty common to need to put terminal boxes in places where working space just is not available, no matter what. So one is kind of forced to make the argument that terminal boxes don't require working space because it is often just a fact that they don't have it and can't get it in any practical way.

110.26 Spaces About Electrical Equipment. Access and
working space shall be provided and maintained about all
electrical equipment to permit ready and safe operation and
maintenance of such equipment.

(A) Working Space. Working space for equipment operating
at 600 volts, nominal, or less to ground and likely to
require examination, adjustment, servicing, or maintenance
while energized shall comply with the dimensions of
110.26(A)(1), (A)(2), and (A)(3) or as required or permitted
elsewhere in this Code.
***
(3) Height of Working Space. The work space shall be
clear and extend from the grade, floor, or platform to a height
of 2.0 m (61⁄2 ft) or the height of the equipment, whichever is
greater. Within the height requirements of this section, other
equipment that is associated with the electrical installation and
is located above or below the electrical equipment shall be
permitted to extend not more than 150 mm (6 in.) beyond the
front of the electrical equipment.
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
I received the following additional information via PM:
dlegrand@lectrus.com said:
My role is Quality Manager for (name deleted) Corporation in Houston, Texas. We build large NEMA 4 enclosures that include Low and Medium voltage equipment integration. Installing utilities and climate control devices.

We are in dispute with our customer concerning junction boxes that have terminal blocks enclosed. The junction boxes are used in continuation of wireway across enclosure splits (many of these enclosures are multiple sections) so on one side of the split a junction box is used as a pull box and on the other side of the split the junction box has a terminal block to terminate wiring across the split. The customer interprets the Junction boxes as electrical equipment therefore requiring it to meet NEC 110.26 for working space clearance, we interpret junction boxes to meet NEC 314.28 which only requires access.

I would greatly appreciate your feedback if we are correct in our interpretation towards NEC 314.28 or if the customer is correct. If you agree with our interpretation can you recommend someone that we can retain to assist us in explaining this interpretation to our customer? Thank You!
My opinion is that this is not likely to require live maintenance, and therefore the 110.26 working clearance rules would not apply.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
I received the following additional information via PM:My opinion is that this is not likely to require live maintenance, and therefore the 110.26 working clearance rules would not apply.
And mine is that is very likely that live troubleshooting will be done at some point on the exposed terminals.
 
The junction boxes are used in continuation of wireway across enclosure splits (many of these enclosures are multiple sections) so on one side of the split a junction box is used as a pull box and on the other side of the split the junction box has a terminal block to terminate wiring across the split.

I read that as the conductors are simply spliced in the box, and those splices use terminal blocks instead of wire nuts or Polaris connectors. Can't see that as needing clearance, and most troubleshooting can be done from other terminals.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Don, we all take live meter readings daily but I fail to see why this box with a terminal strip is any different from one with wire nuts.
This section has serious flaws in the working....as it is written now, it is a violation of 110.26(A) to install the countertop receptacles that are required by 210.52.
Any place or anything where is is likely that it will be worked on or examined while energized it covered by this section....that really includes any device or equipment that you can think of.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Don, I have no idea what the intent was but the word is there, it must be there for a reason and as you so often tell us it is the words in print that matter. :)
The simple definition of require is "to need". It is my opinion that all electrical equipment is likely to "need" "examination,
adjustment, servicing, or maintenance while energized" at some point in its life and, as the section is now written, it applies to all electrical equipment.
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
This section has serious flaws in the working....as it is written now, it is a violation of 110.26(A) to install the countertop receptacles that are required by 210.52.
Any place or anything where is is likely that it will be worked on or examined while energized it covered by this section....that really includes any device or equipment that you can think of.

I thought the code doesn't cover manufactured equipment as far as internals are concerned?
 
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