Explosion-Proof Flex

Status
Not open for further replies.
T

timdiamondz

Member
We have a client who claims that EP flex 18" or less in length cannot be used between the sealoff and the device enclosure. Obviously conduit is allowed per Exhibit 501.6 in Handbook. Cannot find where EP flex is not allowed for last 18". 501.15(A)(1) last paragraph only deals with fittings, not conduit. Any takers on this one?
 
timdiamondz said:
No - I suspect they are trying to use 501.15(A)(1), last paragraph where the type of fittings allowed are described.
Click to expand...
You are correct; they are (improperly) citing:
Conduit seals shall be installed within 450 mm (18 in.)from the enclosure. Only explosionproof unions, couplings, reducers, elbows, capped elbows, and conduit bodies similar to L, T, and Cross types that are not larger than the trade size of the conduit shall be permitted between the sealing fitting and the explosionproof enclosure.
Click to expand...
Why "improperly?" Because "Explosionproof flex" doesn't exist. If you check its listing, you will find it is a "Flexible Coupling" (no matter how long it is).
 
timdiamondz said:
We have a client who claims that EP flex 18" or less in length cannot be used between the sealoff and the device enclosure. Obviously conduit is allowed per Exhibit 501.6 in Handbook. Cannot find where EP flex is not allowed for last 18". 501.15(A)(1) last paragraph only deals with fittings, not conduit. Any takers on this one?
Click to expand...
You are obvious ly refering to the following NEC paragraph.

However I would like to know how you would handle the following 2 cases:

#1 - Explosion proof motor whose junction box is connected to seaoff from underground conduit. area around motor = Cls I Div. II.

#2 - Electronic device in an explosion prf. box installed above gasoline tank. 18" flex between box and seal used for ease of installation and maintenence.


From NEC '08:
501-15 (A)1. Conduit seals shall be installed within 450 mm (18 in.)

from the enclosure. Only explosionproof unions, couplings,

reducers, elbows, capped elbows, and conduit bodies similar

to L, T, and Cross types that are not larger than the trade

size of the conduit shall be permitted between the sealing

fitting and the explosionproof enclosure.
 
casasja said:
You are obvious ly refering to the following NEC paragraph.

However I would like to know how you would handle the following 2 cases:

#1 - Explosion proof motor whose junction box is connected to seaoff from underground conduit. area around motor = Cls I Div. II.

#2 - Electronic device in an explosion prf. box installed above gasoline tank. 18" flex between box and seal used for ease of installation and maintenence.


From NEC '08:
501-15 (A)1. Conduit seals shall be installed within 450 mm (18 in.)

from the enclosure. Only explosionproof unions, couplings,

reducers, elbows, capped elbows, and conduit bodies similar

to L, T, and Cross types that are not larger than the trade

size of the conduit shall be permitted between the sealing

fitting and the explosionproof enclosure.
Click to expand...
In Division 2, you are permitted to use several types of flexible wiring methods. See 501.10(B)(2). However, be sure to observe the grounding and bonding requirements in 501.30 and 250.100.
 
Status
Not open for further replies.
Top