How to bond an explosion-proof motor with no EGC lug?

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Jon456

Jon456

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Colorado
We have an old Baldor pump motor rated for use in hazardous locations. It has an aluminum junction box on the side for connecting the motor leads. This junction box must have been sold as part of the motor because it has a Baldor nameplate on the cover. But inside the junction box, there is no lug or screw terminal to land an EGC for bonding. Nor is there an EGC wire among the potted leads coming from the motor (into the junction box). I've attached a photo of the open junction box. Note, there's no place to attach an EGC to the junction box cover plate either (not pictured).

20170421_143707.jpg

I am using rigid metallic conduit to bring the power conductors to the junction box. I know that metallic can be used as the EGC for non-classified locations; not sure about classified. But even if using the conduit alone is permissible, I would prefer a dedicated EGC wire.

Thoughts & recommendations?
 
After I posted the photo, I noticed the nipple of the explosion-proof union was protruding into the junction box by a couple of threads. I could possibly install a conduit grounding bushing, although I'm not sure if it would have sufficient thread engagement.

Z07Ctwfo5oy.jpg
 
Section 430.12(E) and its Exception has been around in some form or other since before I was in the business. Unless the Exception applies, you have a non-compliant motor, explosionproof or not.
 
Someone needs to get on Baldor for the crap they put out. I have had many issues with them on their hydraulic pool cover openers.
 
Looks like it has threaded hub on back side, just replace the box with one that has a grounding lug/screw.
 
Boy, that sucks. And this pump & motor have been in service here for decades. I'm just upgrading the system and noticed this. I'll take Kwired's advice and replace the junction box. Unfortunately, I've already bent and installed all the rigid conduit. :weeping:
 
Dennis Alwon said:
I would think that changing the enclosure would void the listing.

Are running RMC directly to the pump?
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Motors often are not listed, though hazardous location motors maybe are.

The box may or may not be part of any listing as well.

Changing box is still a better solution then drilling a bonding screw into the box.
 
kwired said:
Motors often are not listed, though hazardous location motors maybe are.

The box may or may not be part of any listing as well.

Changing box is still a better solution then drilling a bonding screw into the box.
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At one time, explosionproof motors were the only class that were listed. Recently some motors have been listed specifically for Division 2 and a few have recently been listed for "general purpose". At this time, those "general purpose" listings are universally by foreign manufacturers. The NEMA motor group continues to avoid seeking listing for the membership's "general purpose" motors.

The motor terminal box is always part of the listing for explosionproof motors. It can only be installed by the manufacturer.

Drilling an explosionproof motor's enclosure at any location, including the footing, technically voids the listing.
 
Just to clarify, the wiring enclosure on this Baldor motor is UL listed for Class I and Class II hazardous locations. How is that possible if a bonding terminal is required?

20170425_180148.jpg

Based on Rbalex's last post, it would seem the only 100% code-compliant recourse is to replace the motor with a new one. But my company simply will not pay for a new motor when the existing one has been operating as it has been for so many years. I hate doing this because I'm a stickler for doing things right, but it seems I have the following choices:

1. Do nothing. Reinstall the pump & motor as it was originally installed years ago with no dedicated EGC.

2. Install an EGC into the existing junction box with a conduit grounding bushing (assuming I can get it engaged on the nipple protrusion).

3. Drill and tap the existing junction box for a bonding terminal.

4. Replace the existing junction box with a new one that has a bonding terminal.

5. Possibly weld an aluminum bonding lug inside the existing junction box. I'm hesitant to do this since I don't know the aluminum alloy and it might bugger the whole thing up.
 
petersonra said:
or you cold call baldor and ask them how this is supposed to meet code. maybe there is something none obvious.
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In bet you one junction box that they tell you to replace the box, if necessary with one they provide to you, which is very well same thing you can buy elsewhere just has been "rebranded".
 
Jon456 said:
Just to clarify, the wiring enclosure on this Baldor motor is UL listed for Class I and Class II hazardous locations. How is that possible if a bonding terminal is required?

View attachment 17431

Based on Rbalex's last post, it would seem the only 100% code-compliant recourse is to replace the motor with a new one. But my company simply will not pay for a new motor when the existing one has been operating as it has been for so many years. I hate doing this because I'm a stickler for doing things right, but it seems I have the following choices:

1. Do nothing. Reinstall the pump & motor as it was originally installed years ago with no dedicated EGC.

2. Install an EGC into the existing junction box with a conduit grounding bushing (assuming I can get it engaged on the nipple protrusion).

3. Drill and tap the existing junction box for a bonding terminal.

4. Replace the existing junction box with a new one that has a bonding terminal.

5. Possibly weld an aluminum bonding lug inside the existing junction box. I'm hesitant to do this since I don't know the aluminum alloy and it might bugger the whole thing up.
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Your photo indicates the motor terminal box is listed as a Class I & II outlet box; it says nothing about the motor itself.

Option #1 may be OK if Section 430.12(E), Exception applies. This is possible; I don't know the full extent of the original installation. I would not contact Baldor, I would contact UL. Their Northbrook Illinois lab (847-272-8800) is their dominant, although not exclusive, Hazloc testing facility.

IMO option #2 may be viable if you can convince yourself (and the AHJ) it is consistent with Section 501.30.

Option #4 may also be acceptable with the AHJ's blessing.

Options #3 & 5 are definite no-nos; they will violate the listing.
 
rbalex said:
Option #1 may be OK if Section 430.12(E), Exception applies. This is possible; I don't know the full extent of the original installation.
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The exception did not apply when the pump/motor were originally installed, and it does not apply now.
 
rbalex said:
In my response, Option #2 is installing an EGC (that meets Section 501.30).
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And that makes it seem like a metal conduit by itself cannot qualify as the only EGC. 501.30(B) only requires a wire-type EBJ for FMC and LFMC. The key here is that 501.30(A) does not explicitly require a wire-type EBJ.
501.30 Grounding and Bonding, Class I, Divisions 1and 2. Regardless of the voltage of the electrical system,
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-locknuttypes 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.
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250.100 Bonding in Hazardous (Classified) Locations.
Regardless of the voltage of the electrical system, the electrical
continuity of non–current-carrying metal parts of
equipment, raceways, and other enclosures in any hazardous
(classified) location, as defined in 500.5, 505.5, and
506.5, shall be ensured by any of the bonding methods
specified in 250.92(B)(2) through (B)(4). One or more of
these bonding methods shall be used whether or not equipment
grounding conductors of the wire type are installed.
Informational Note: See 501.30, 502.30, 503.30, 505.25, or
506.25 for specific bonding requirements.
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250.92 Services.
...


(B) Method of Bonding at the Service. Bonding jumpers
meeting the requirements of this article shall be used around
impaired connections, such as reducing washers or oversized,
concentric, or eccentric knockouts. Standard locknuts or bushings
shall not be the only means for the bonding required by
this section but shall be permitted to be installed to make a
mechanical connection of the raceway(s).
Electrical continuity at service equipment, service raceways,
and service conductor enclosures shall be ensured by
one of the following methods:

(1) Bonding equipment to the grounded service conductor
in a manner provided in 250.8

(2) Connections utilizing threaded couplings or threaded
hubs on enclosures if made up wrenchtight

(3) Threadless couplings and connectors if made up tight
for metal raceways and metal-clad cables

(4) Other listed devices, such as bonding-type locknuts,
bushings, or bushings with bonding jumpers
Click to expand...
 
Smart $ said:
And that makes it seem like a metal conduit by itself cannot qualify as the only EGC. 501.30(B) only requires a wire-type EBJ for FMC and LFMC. The key here is that 501.30(A) does not explicitly require a wire-type EBJ.
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When we began this thread my initial response (#3) was the motor was not compliant with Section 430.12(E) unless its Exception applied. The fact is the motor doesn't comply with UL's requirements for explosionproof motors or NEMA's MG-1 for motor terminal housings in general. Now, under the Standards just cited and unless a specific exception applies, the NEC, UL, and NEMA all require "... a means for attachment of an equipment grounding conductor termination in accordance with 250.8 ..." (or similar terminology). HOWEVER, none of them require an actual wire EGC to be used - only a "means" to do so, whether used or not.

My subsequent response (#12) didn't say a wire EGC was required for Option #2 either, simply that an EGC compliant with Section 501.30 was required. A wire may be the easiest to show compliance but certainly isn't exclusive and I didn't say (or imply) it was.

Your desire that everything be laid out in a single unambiguous location (or answer) is a prime example of the last sentence of Section 90.1(A) [2017]. (The phrase about "untrained persons" doesn't apply in this particular case ;).)

I do appreciate your citing the other relevant Code Sections (although you missed Section 250.8 :p)
 
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