Wire Splicing in Hazardous Locations

[Markmy]

What type of conduit fittings can be used for the wire splicing (120/240VAC) in hazardous Class I Div 2 areas.

 

[Dennis Alwon]

What type of conduit fittings can be used for the wire splicing (120/240VAC) in hazardous Class I Div 2 areas.

What type of system are you wiring? If your wiring falls into those sections below then you would need explosion proof. Is this what you are looking for?

From the 2017

Boxes and Fittings. Boxes and fittings shall not be
required to be explosionproof except as required by
501.105(B)(2), 501.115(B)(1) , and 501.150(B)(1).

 

[Markmy]

I have some process switches (not factory sealed) at tank farm class I div 2 area, which wires need to be extended to the field control panel. So I need to make splices in the fittings. The type of fitting is my concern.

 

[don_resqcapt19]

I have some process switches (not factory sealed) at tank farm class I div 2 area, which wires need to be extended to the field control panel. So I need to make splices in the fittings. The type of fitting is my concern.

No special requirements for the enclosure used to make the splices. You do need to make sure that the switch is rated for Class I, Division 2, which will require an explosionproof housing, and you will need to provide the correct seal at the process switch. This seal will have to be before you splice the conductors. See the last part of 501.15(A)(1) which is referenced in 501.15(B)(1) for enclosure seals in a Class I, Division 2 location.

 

[Markmy]

No special requirements for the enclosure used to make the splices. You do need to make sure that the switch is rated for Class I, Division 2, which will require an explosionproof housing, and you will need to provide the correct seal at the process switch. This seal will have to be before you splice the conductors. See the last part of 501.15(A)(1) which is referenced in 501.15(B)(1) for enclosure seals in a Class I, Division 2 location.

Thanks, Don. Yes, NEC provides clear instructions about seals in hazardous areas, but nothing about splices. I always believed than round box withc

No special requirements for the enclosure used to make the splices. You do need to make sure that the switch is rated for Class I, Division 2, which will require an explosionproof housing, and you will need to provide the correct seal at the process switch. This seal will have to be before you splice the conductors. See the last part of 501.15(A)(1) which is referenced in 501.15(B)(1) for enclosure seals in a Class I, Division 2 location.

Thanks, Dan. Yes, NEC is very clear about seals, but there is nothing I can find about splicing in hazardous locations. I always thought that explosioproof box with screw type cover and threaded hubs should be used for wire splices in Class1 Div. 1 & 2 areas.

 

[rbalex]

Fundamentally, the rules for splicing are no different in hazardous locations than in common locations. They do need to be included as part of one of the wiring methods listed in Section 501.10(A)(1) or (B)(1).

In Division 1, virtually every enclosure (conduit fittings included) is required to be explosionproof. [Section 501.10(A)(3)] There are other options, such as purged/pressurized, but they are usually not cost effective.

Division 2 is more liberal. As long as the wiring method is one in Section 501.10(B)(1), only enclosures listed in Section 501.10(B)(4) require special attention.

 

[Markmy]

Fundamentally, the rules for splicing are no different in hazardous locations than in common locations. They do need to be included as part of one of the wiring methods listed in Section 501.10(A)(1) or (B)(1).

In Division 1, virtually every enclosure (conduit fittings included) is required to be explosionproof. [Section 501.10(A)(3)] There are other options, such as purged/pressurized, but they are usually not cost effective.

Division 2 is more liberal. As long as the wiring method is one in Section 501.10(B)(1), only enclosures listed in Section 501.10(B)(4) require special attention.

Thanks Robert, for your input.

 

[4-20mA]

Also, mark it/redline or make a note of it on the loop sheet or other drawings too. Someone troubleshooting later will thank you for it. Might even be yourself.

 

[Markmy]

Also, mark it/redline or make a note of it on the loop sheet or other drawings too. Someone troubleshooting later will thank you for it. Might even be yourself.

We don’t typically show the splices on the loop diagrams. But, it maybe a good idea, especially if wires colors were changed. Thanks.

 

[4-20mA]

We don’t typically show the splices on the loop diagrams. But, it maybe a good idea, especially if wires colors were changed. Thanks.

Yessir I know it's not a typical practice... thing is, troubkeshot for a day and you've hand over fisted nasty old cable tray for 100's of feet to realize someone spliced wires in an LB you wish like hell someone left you a note somewhere... ask me how I know... I realize not everyone works in a nasty old plant like myself but jist throwing it out there. You're welcome.

 

[4-20mA]

Yessir I know it's not a typical practice... thing is, troubkeshot for a day and you've hand over fisted nasty old cable tray for 100's of feet to realize someone spliced wires in an LB you wish like hell someone left you a note somewhere... ask me how I know... I realize not everyone works in a nasty old plant like myself but jist throwing it out there. You're welcome.

Just wanted to say that my thank you at the end there is not snarky and not meant to come off that way but reading it back seems like it could be taken wrong and I don't want that to happen here. It was/is genuine!

 

[don_resqcapt19]

...
Thanks, Dan. Yes, NEC is very clear about seals, but there is nothing I can find about splicing in hazardous locations. I always thought that explosioproof box with screw type cover and threaded hubs should be used for wire splices in Class1 Div. 1 & 2 areas.

It is covered by 501.10(B)(4), but you kind of have to read between the lines to understand that. You go to the sections referenced in (B)(4) and if your enclosure is not covered by any of those, and enclosure that is envriomentally suitable for the area can be used as a splice box.