Sealing fitting in class 1 div2

[hamzazayyad]

Hi,

I would like to know if the sealing fitting is required in the following cases:-

1- the motor is explosion proof but is has internal switch(thermostat switch) !!!!
2- the switch(pressure switch) is certified as explosion proof switch but these is no label on the switch to indicate that it is factory sealed switch !!!
3- do we need to add sealing fitting to the terminal box(junction box that has only terminasl to connect the wires) ???(that does not has make and break or high temp ??

Thanks..

 

[rbalex]

Hi,

I would like to know if the sealing fitting is required in the following cases:-

1- the motor is explosion proof but is has internal switch(thermostat switch) !!!!
2- the switch(pressure switch) is certified as explosion proof switch but these is no label on the switch to indicate that it is factory sealed switch !!!
3- do we need to add sealing fitting to the terminal box(junction box that has only terminasl to connect the wires) ???(that does not has make and break or high temp ??

Thanks..

1. If there is a factory seal between the motor and the motor terminal box, no. Otherwise, yes.
2. Without evidence of a factory seal, a seal is required for an explosionproof enclosure.
3. Assuming we aren?t discussing the same motor as item one, no seal is necessary in Division 2.

I note you are in Jordan. Are the motors we are discussing NEMA/NEC or IEC rated? My answers are based on NEMA/NEC.

 

[rbalex]

I had a friend call me on this. (Literally - 1600 miles away) The answer to item 3 is not absolutely correct. While there is no requirement for a seal for the motor terminal box itself there may be a non-explosionproof seal at or near the motor terminal box for "boundary" purposes. Again, this applies to NEMA/NEC applications.

 

[hamzazayyad]

1. If there is a factory seal between the motor and the motor terminal box, no. Otherwise, yes.
2. Without evidence of a factory seal, a seal is required for an explosion proof enclosure.
3. Assuming we aren?t discussing the same motor as item one, no seal is necessary in Division 2.

I note you are in Jordan. Are the motors we are discussing NEMA/NEC or IEC rated? My answers are based on NEMA/NEC.

thank you for your reply.note: the location is classified as class 1 div 2 and i will install the unit (motors and switches....) inside this location.for point no 1 the motor is NEMA frame and certified for class 1 div1 and the thermostat(switch) is installed on the motor windingin this case there is no make or brake( ignition source) inside motor terminal box, so, there is no need to add the sealing fitting on the motor terminal box,is this correct???for point no 2 (note: this switch is certified as class 1 div 1)I found a label on the switch that indicate that ''this switch is factory sealed lead wire'',so, is this equivalent to factory sealed??? because there is an exception as below(point no c)Exception to 501.5(A)(1)(1): Seals shall not be required forconduit entering an enclosure where such switches, circuitbreakers, fuses, relays, or resistors are(a) Enclosed within a chamber hermetically sealed againstthe entrance of gases or vapors, or(b) Immersed in oil in accordance with 501.6(B)(1)(2), or(c) Enclosed within a factory-sealed explosionproof chamberlocated within the enclosure, identified for the location,and marked ?factory sealed? or equivalent, unlessthe enclosure entry is metric designator 53 (tradesize 2) or larger.do we need to add a seal???point no 3we have explosion proof junction box(certified) and we need to use it as terminal box(just to connect the wires together inside it) and there is no switches or high temp inside itso, there is no need to add a seal (CL 1 DIV 2), is this correct??Additional question:-I think all IEC components that has IEEX or ATEX are not allowed to be used in class/div location (nec 500 ,north america) blouse it has differate certifications>>>is this correct??thanks and I am waiting your reply.

 

[rbalex]

thank you for your reply.note: the location is classified as class 1 div 2 and i will install the unit (motors and switches....) inside this location.for point no 1 the motor is NEMA frame and certified for class 1 div1 and the thermostat(switch) is installed on the motor windingin this case there is no make or brake( ignition source) inside motor terminal box, so, there is no need to add the sealing fitting on the motor terminal box,is this correct???for point no 2 (note: this switch is certified as class 1 div 1)I found a label on the switch that indicate that ''this switch is factory sealed lead wire'',so, is this equivalent to factory sealed??? because there is an exception as below(point no c)Exception to 501.5(A)(1)(1): Seals shall not be required forconduit entering an enclosure where such switches, circuitbreakers, fuses, relays, or resistors are(a) Enclosed within a chamber hermetically sealed againstthe entrance of gases or vapors, or(b) Immersed in oil in accordance with 501.6(B)(1)(2), or(c) Enclosed within a factory-sealed explosionproof chamberlocated within the enclosure, identified for the location,and marked ?factory sealed? or equivalent, unlessthe enclosure entry is metric designator 53 (tradesize 2) or larger.do we need to add a seal???point no 3we have explosion proof junction box(certified) and we need to use it as terminal box(just to connect the wires together inside it) and there is no switches or high temp inside itso, there is no need to add a seal (CL 1 DIV 2), is this correct??Additional question:-I think all IEC components that has IEEX or ATEX are not allowed to be used in class/div location (nec 500 ,north america) blouse it has differate certifications>>>is this correct??thanks and I am waiting your reply.

Your original post was much easier to decipher. Please use an occasional paragraph.

As I understand you:

#1. The electrical area classification is Class I, Division 2 per the NEC.

#2. The motor is identified for Class I, Division 1. It has a thermal switch on the motor windings but no arcing, sparking or heating elements in the motor terminal box. My original response (originally Item #1) still stands. While the motor is not required to be identified for Division 1, unless there is a factory seal between the motor housing and the motor terminal box, there must be an external raceway/cable seal because the internal switch can still produce an arc.

#3. The pressure switch appears to now indicate that is indeed ?factory sealed? internally. No external seal is necessary for the switch. The Exception in Section 501.5(A)(1) and all Division 1 references you cited after that are irrelevant.

#4. Again, assuming we are not discussing the motor in Item 2 above (originally Item #1), you have a motor terminal box that is identified for Division 1, but is not required to be. No seal is necessary for the terminal box unless there is an internal thermal switch in the motor housing.

#5. In all the discussions above, a boundary seal may be needed. Whether it is at or near a motor or pressure switch is determined by the installation.

#6. Components that are only IEC or ATEX rated are not suitable for NEC applications - hazardous locations or not. Some AEx (US) Zone rated devices are permitted in Division 2.

 

[hamzazayyad]

Your original post was much easier to decipher. Please use an occasional paragraph.

As I understand you:

#1. The electrical area classification is Class I, Division 2 per the NEC.

#2. The motor is identified for Class I, Division 1. It has a thermal switch on the motor windings but no arcing, sparking or heating elements in the motor terminal box. My original response (originally Item #1) still stands. While the motor is not required to be identified for Division 1, unless there is a factory seal between the motor housing and the motor terminal box, there must be an external raceway/cable seal because the internal switch can still produce an arc.

#3. The pressure switch appears to now indicate that is indeed ?factory sealed? internally. No external seal is necessary for the switch. The Exception in Section 501.5(A)(1) and all Division 1 references you cited after that are irrelevant.

#4. Again, assuming we are not discussing the motor in Item 2 above (originally Item #1), you have a motor terminal box that is identified for Division 1, but is not required to be. No seal is necessary for the terminal box unless there is an internal thermal switch in the motor housing.

#5. In all the discussions above, a boundary seal may be needed. Whether it is at or near a motor or pressure switch is determined by the installation.

#6. Components that are only IEC or ATEX rated are not suitable for NEC applications - hazardous locations or not. Some AEx (US) Zone rated devices are permitted in Division 2.

thank you for your support.

is it permitted to use ex proof switch that has UL listed and FM approval class 1 div1??? is the FM certification acceptable for NEC applications(class 1 div2)??

 

[rbalex]

Since you appear to have an NEC available, see Section 500.8(C). Read all of it carefully, especially 500.8(C)(2) and its FPN/IN. Whether something is required to be identified for Division 1 or not, a Division 1 product is acceptable in Division 2. The sealing requirements may differ. Divison 1 will usually be more rigorous than Division 2, but never less.

There are several Nationally Recognized Testing Laboratories (NRTL) for certifying hazardous location products. FM is one of them. Historically, UL usually certified to NEC Divisions, FM usually certified to NEC Zones, but that is not a "hard and fast" rule for either of them.

 

[hamzazayyad]

rbalex thank you for your support .

I have another question for boundary seal between calss 1 div2 and unclassified location
as per nec code we need to add a seal in hazardous location (or unclassified location)but within 10 ft of the boundary and the leaving point from seal fitting to unclassified location must be rigid metal conduit (RMC).

in this case

1-can we use liquid tight conduit in class 1 div 2 and RMC for the leaving conduit in the same time???
2- can we connect the RMC(for leaving conduit) to general purpose elbow in unclassified location then to plastic hose then general purpose electric panel in unclassified location.
or we must connect RMC to general purpose electric panel in unclassified location.

plz see below pic

thank you. View attachment 8725

 

[rbalex]

The location of the seals as shown in the diagram is acceptable; HOWEVER, you are running afoul of grounding/bonding requirements in NEC Section501.30. FURTHERMORE, “plastic hose” is unacceptable in any NEC installation - classified or not.

At this point, I recommend you secure the services of a design professional that understands hazardous location. See NEC Section 90.1(C)

 

[hamzazayyad]

thanks for support.

NOTE:- i need the data for guidance not to make explosion proof project.

Sorry, in the above diagram the conduit is liquidtight flexible metal conduit(LFMC) not LFNM.
D o mean that I need to add bonding jumper every 6ft for LFMC??

also do you mean that we need to connect RMC from the seal to electrical panel directly(cl 1 div2 to unclassified location)..

plz advice...

 

[rbalex]

It wasn't showing LFNM either; it was LFNB. And ?plastic hose? still isn't acceptable as a raceway in any NEC location.

Read Section 250.118 (5) & (6) very carefully, especially 250.118 (5)(c) & (6)(d). Hint: bonded every six feet or not the LFMC is still in the ground-fault current path.

Also read and understand, especially the underlined and bolded part of Section 501.30 below:.

501.30 Grounding and Bonding, Class I, Divisions 1and 2. Wiring and equipment in Class I, Division 1 and 2 locations shall be grounded as specified in Article 250 and in accordance with the requirements of 501.30(A) and (B).
(A) Bonding. The locknut-bushing and double-locknut types of contacts shall not be depended on for bonding purposes, but bonding jumpers with proper fittings or other approved means of bonding shall be used. Such means of bonding shall apply to all intervening raceways, fittings, boxes, enclosures, and so forth between Class I locations and the point of grounding for service equipment or point of grounding of a separately derived system...

You should have started a new thread as you did with "RTD and NTC sensor" since this no longer deals with sealing.


You may also want to review this thread.

 

[hamzazayyad]

rbalex thank you for your support .

I have another question for boundary seal between calss 1 div2 and unclassified location
as per nec code we need to add a seal in hazardous location (or unclassified location)but within 10 ft of the boundary and the leaving point from seal fitting to unclassified location must be rigid metal conduit (RMC).

in this case

1-can we use liquid tight conduit in class 1 div 2 and RMC for the leaving conduit in the same time???
2- can we connect the RMC(for leaving conduit) to general purpose elbow in unclassified location then to plastic hose then general purpose electric panel in unclassified location.
or we must connect RMC to general purpose electric panel in unclassified location.

plz see below pic

thank you.

1

 

[hamzazayyad]

OK. plz see below

in case OCPD is less than 10A and I added internal ground conductor(bounding) for each motor terminal box, switch box,junction box and explosion proof union for each component like motor,switch..ect. do i need to add addition locknut ???i think now there is no ground-fault current path with LFMC!!!!!.


View attachment 8742

 

[rbalex]

OK. plz see below

in case OCPD is less than 10A and I added internal ground conductor(bounding) for each motor terminal box, switch box,junction box and explosion proof union for each component like motor,switch..ect. do i need to add addition locknut ???i think now there is no ground-fault current path with LFMC!!!!!.


View attachment 8742

You didn?t read Sections 250.118 (5)(c) & (6)(d) carefully enough. The total LFMC in the current path must be less than 6 feet. Even if each section of LFMC were less than 6 feet the total may still exceed it.

Second, as I said earlier, ?bonded every six feet or not the LFMC is still in the ground-fault current path.? There will still be a current divider between the bond and the LFMC.

Third, don?t use the exception until you understand the basic rule.

 

[GoldDigger]

Second, as I said earlier, ?bonded every six feet or not the LFMC is still in the ground-fault current path.? There will still be a current divider between the bond and the LFMC.

Dielectric coupling?

 

[rbalex]

Dielectric coupling?

I certainly hope you?re joking. In any case, I?d appreciate you not introducing extraneous drivel where the OP author is obviously having a hard time understanding the basic subject.

In 2005 and earlier, it would be easier to address your comment. Section 501.30(B)[2005] said:

(B) Types of Equipment Grounding Conductors. Where flexible metal conduit or liquid tight flexible metal conduit is used as permitted in 501.10(B) and is to be relied on to complete a sole equipment grounding path, it shall be installed with internal or external bonding jumpers in parallel with each conduit and complying with 250.102.

A? dielectric coupling? would make the LFMC in series at best.


Unfortunately, through the joys of unintended consequences the revised Section 501.30(B) leaves the reference to ?parallel? out. It now takes references to Sections 250.92, 250.100, 250.102, 250.118 and back to 501.130 since grounding/bonding requirements applies to both Division 1 and 2 to arrive at the same conclusion. Depending on where the ground-fault occurred the LFMC could still be in the ground-fault current path. In Division 1 ?could? is all it takes.

 

[hamzazayyad]

You didn?t read Sections 250.118 (5)(c) & (6)(d) carefully enough. The total LFMC in the current path must be less than 6 feet. Even if each section of LFMC were less than 6 feet the total may still exceed it.

Second, as I said earlier, ?bonded every six feet or not the LFMC is still in the ground-fault current path.? There will still be a current divider between the bond and the LFMC.

Third, don?t use the exception until you understand the basic rule.

thank you for the support.
in case the total length for LFMC is less 6 ft,OCPD<20A,Termination fitting is Straight LFMC Connector and 1/2'' LFMC and with internal earth conductor, so this will be good for 250.118 (5),250.118 (6) and there is no problem with ground-fault current path, is this correct??


but, how can use(install) LFMC in unlimited length without a problem with ground-fault current path ???

 

[rbalex]

thank you for the support.
in case the total length for LFMC is less 6 ft,OCPD<20A,Termination fitting is Straight LFMC Connector and 1/2'' LFMC and with internal earth conductor, so this will be good for 250.118 (5),250.118 (6) and there is no problem with ground-fault current path, is this correct??
?

There is no such thing as an ?earth conductor? in the NEC, The internal conductor would be a equipment bonding jumper, or effectively, an equipment grounding conductor. A straight LFMC connector must be used with an enclosure that allows 5 full threads engagement; wrench tight. It will probably also require a union. Otherwise you will need a listed grounding/bonding bushing.

?
but, how can use(install) LFMC in unlimited length without a problem with ground-fault current path ???

LFMC cannot be used in an unlimited length either with or without a bonding jumper in a hazardous location. In unclassified locations study Article 350.

 

[hamzazayyad]

There is no such thing as an ?earth conductor? in the NEC, The internal conductor would be a equipment bonding jumper, or effectively, an equipment grounding conductor. A straight LFMC connector must be used with an enclosure that allows 5 full threads engagement; wrench tight. It will probably also require a union. Otherwise you will need a listed grounding/bonding bushing.
LFMC cannot be used in an unlimited length either with or without a bonding jumper in a hazardous location. In unclassified locations study Article 350.

but why we need union or grounding/bonding bushing in case I used listed termination fitting and LFCM<6FT ???
also using grounding/bonding bushing there will be two equipment bonding jumper(internal and external)???

 

[rbalex]

but why we need union or grounding/bonding bushing in case I used listed termination fitting and LFCM<6FT ???
also using grounding/bonding bushing there will be two equipment bonding jumper(internal and external)???

Have you read this thread as I suggested ? I don't care to repeat it all again.