Storage and waste room hazardous boundary

[hhsting]

I have class 1 division 2 hazardous storage room and waste room in commercial setting lab. The light switches controlling the room were inside before but now the designer has moved the light switches from the inside to the outside walls of the room. So now light switches are outside the room.

I suspect he did this because he did not want to provide explosion proof light switches or to meet light switch with 500.5.

Is their NEC 2014 requirement for light switches to be inside or outside the storage room and waste room?

 

[augie47]

No

 

[gadfly56]

I have class 1 division 2 hazardous storage room and waste room in commercial setting lab. The light switches controlling the room were inside before but now the designer has moved the light switches from the inside to the outside walls of the room. So now light switches are outside the room.

I suspect he did this because he did not want to provide explosion proof light switches or to meet light switch with 500.5.

Is their NEC 2014 requirement for light switches to be inside or outside the storage room and waste room?

Regardless of inside or outside, if the architect has moved the switch to the outside to avoid using an XP switch be aware that the classified area boundary extends beyond the threshold of the door into the general space. I forget the exact amount, but 3-5 feet sticks in my head. That's a radius on the plan view from each edge of the door and across the front of the door. If the switch is that far from the room, someone my have an issue with that.

 

[hhsting]

Regardless of inside or outside, if the architect has moved the switch to the outside to avoid using an XP switch be aware that the classified area boundary extends beyond the threshold of the door into the general space. I forget the exact amount, but 3-5 feet sticks in my head. That's a radius on the plan view from each edge of the door and across the front of the door. If the switch is that far from the room, someone my have an issue with that.

Where is this in NEC 2014?


Sent from my iPhone using Tapatalk

 

[gadfly56]

Where is this in NEC 2014?


Sent from my iPhone using Tapatalk

See figure 516.3(D)(4)(1). The closest I can think of to your situation. However, this is not engineering advice per se. Someone who is experienced in the classification of hazardous areas needs to look at your situation and make a determination. That's not happening via blog posts.

 

[tom baker]

The NEC is very clear area classification documentation is to be provided, See 500,4 and all the INs (check the 2014 there are changes in this section for 2020. The area classifications would be shown on the plans. The designer will need to find someone to properly document this, its not your call.

 

[augie47]

Your erngineered drawings should identify the hazardous area (and boundaries).
I suggest you tread softly as a plans reviewer when dealing with a Classified area.
That's one area where the P.E. definitely earns his keep.

500.4 General.
(A) Documentation. All areas designated as hazardous
(classified) locations shall be properly documented. This
documentation shall be available to those authorized to design,
install, inspect, maintain, or operate electrical equipment
at the location.

 

[hhsting]

See figure 516.3(D)(4)(1). The closest I can think of to your situation. However, this is not engineering advice per se. Someone who is experienced in the classification of hazardous areas needs to look at your situation and make a determination. That's not happening via blog posts.

I don’t have spray booth NEC 2014 section 516 is for spray booth application. Mine is lab setting

 

[hhsting]

Your erngineered drawings should identify the hazardous area (and boundaries).
I suggest you tread softly as a plans reviewer when dealing with a Classified area.
That's one area where the P.E. definitely earns his keep.

500.4 General.
(A) Documentation. All areas designated as hazardous
(classified) locations shall be properly documented. This
documentation shall be available to those authorized to design,
install, inspect, maintain, or operate electrical equipment
at the location.

PE has classified hazardous boundary extent but starting from outside wall of those rooms everything is non hazardous

 

[don_resqcapt19]

PE has classified hazardous boundary extent but starting from outside wall of those rooms everything is non hazardous

If you have an area classification drawing that is all you need. You install the electrical in accordance with the classifications as shown on the drawing.