LFMC entering a threaded motor peckerhead - proper install?

E

emiller233

Senior Member
Location
pittsburgh, pa
Occupation
Controls-Automation engineer
We have a motor with a threaded conduit hole on the peckerhead. The shop guys tell me the conduit hub won't fully thread onto it (making the gasketed seal). That there's still about 1/4" of thread left before the gasket would make the seal to the peckerhead.
And putting the 45-degree LFMC fitting directly onto the peckhead is not permitted, and we shall use a hub, correct?
They want to grind the threads out of the conduit opening so the hub makes the gasketed seal.
What is the proper way to install this?
Also, are there any other APPROVED methods for securing the LFMC? The only one I've found that lists LFMC specifically is an Arlington

3" conduit opening to 1-1/4" LFMC (75HP motor)

This needs to meet Canadian code as well


parts list for motor connection
  • hub
    • 3" CONDUIT HUB
      • CROUSE-HINDS ST 8
  • reducers
    • RIGID CONDUIT REDUCER, 3" to 1-1/2" NPT
      • CROUSE-HINDS 288
    • RIGID CONDUIT REDUCER, 1-1/2" to 1-1/4" NPT
      • CROUSE-HINDS 275
  • LFMC fitting
    • 1-1/4" LFMC FITTING, 45° ANGLE, INSULATED"
      • CROUSE-HINDS LTB12545
  • LFMC clamp
    • Arlington NM2050
motor peckerhead
1755790744419.png

LFMC layout
1755790978932.png

overview
1755791204875.png

1755791428769.png
 

Attachments

  • non-metallic conduit clamps - Quicklatch.pdf
    350.1 KB · Views: 0
emiller233 said:
The shop guys tell me the conduit hub won't fully thread onto it (making the gasketed seal). That there's still about 1/4" of thread left before the gasket would make the seal to the peckerhead.
Click to expand...
What kind of conduit hub are you referencing? You have a 3" threaded opening in the peckerhead that you're connecting a 1¼" LFMC to?
 
infinity said:
What kind of conduit hub are you referencing? You have a 3" threaded opening in the peckerhead that you're connecting a 1¼" LFMC to?
Click to expand...
Myers hub i think is what most folks call them. then reduce down to 1-1/4" LFMC.
but might have to only go down to 1-1/2" LFMC, just bc the clamps i listed dont have a 1-1/4" option...

1755792556044.png
reducer

1755792782474.png
 
I would use a 3" to 1¼" reducer and thread the LFMC connector into that. A Myers hub is not necessary.

SouthwireCo_RB21.jpg


 
infinity said:
I would use a 3" to 1¼" reducer and thread the LFMC connector into that. A Myers hub is not necessary.

SouthwireCo_RB21.jpg


Click to expand...
no hub and LFMC fittings directly into the motor peckerhead meets code? i was told it did NOT and inspectors may fail it. Thats the only reason they're on there.
does it matter if the conduit opening is NPT threaded vs just a non-threaded opening? they said we have to use it entering every disconnect enclosure as well (UL508A certified builds)
 
emiller233 said:
no hub and LFMC fittings directly into the motor peckerhead meets code? i was told it did NOT and inspectors may fail it.
Click to expand...
What code section does it violate? In fact since a LFMC connector has straight threads it can only be used with a locknut and cannot thread into anything so a Myers hub or a threaded reducer won't change anything. We would always use a threaded reducer with the connector because there is no other sensible option.

Also after looking at the graphics if this a listed package unit an electrical
Inspector out in the field can't say anything about how a listed unit is constructed.
 
If the thread won't bottom, screw on a locknut with the teeth facing the housing, then lock it down with the connector snugged up.
 
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