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Joined: Jan 2005
Posts: 109
Grover Offline OP
Opinions? Experiences? Old school boss wants setscrew terminations - I favor proper die hydraulic crimp. Application is parallel runs - 1200 A 480 3 phase. Total of 64 terminations.

Square D QED Switchboard provides setscrew lugs for 32 of the terminations - what do do with the rest?

Appreciate input.


Joined: Apr 2002
Posts: 7,372
Likes: 7
4 conductors per phase??
or ???
64 terminations; I'm assuming switchboard to padmount xfr? At 4 per phase...16 and 16..

I'm confused. I'm 'old school' too (59), but I'm partial to crimp terminations.

I've done setscrew lugs (factory installed in gear) and crimps at the padmount supplied by me, installed by me. Our utility requires EC's to do secondary terminations at padmounts.


Joined: Jan 2005
Posts: 109
Grover Offline OP
Hotline - sorry to confuse....

4 pipes - A,B,C,N in each - parallel.

Genset ->Switchgear, Switchgear to MCC

Switchgear has setscrew lugs supplied - Square D QED.

My old school guy has apparetly had trouble with failed crimps (wrong die, not enough pressure?). QED ame with setscrew lugs - weakens my arguement.

I've always used crimps with no complaints...


Joined: Nov 2006
Posts: 348
ITO Offline
What do the specs say, and what type of terminations did you submit on?

101° Rx = + /_\
Joined: Nov 2000
Posts: 2,148
I will normally toss out the manufacture provided set screw connectors and replace them with compression connectors on equipment of that size. We always use a dieless hydraulic crimper so there is no problem with the wrong die or incorrect pressure. For that many terminations I would be using the cordless hydraulic crimper in place of the hand pumped one.

Joined: May 2003
Posts: 2,876
e57 Offline
Odds are that the manufacturer makes lugs for the purpose. I've seen 6 and 8 hole lugs like that, and four hole are pretty common. If you dig through the SqD catolog I'll bet you find them. Properly torqued they are just as good a connection IMO.

If you crimped them all - what would you be doing for all the connections to the busswork? Does it have bolt patterns for that? Dont 500MCM crimps have 2-bolts per?

Mark Heller
"Well - I oughta....." -Jackie Gleason
Joined: Nov 2000
Posts: 2,148
Crimps are made in either single or two hole type. Many of the larger mechanical lugs are two hole with the same pattern as the crimps.
Properly torqued they are just as good a connection IMO.

In my opinion a properly installed mechanical lug is never as good as a properly installed compression lug. Both will do the job, however I believe that the compression are better. The contact pressure on the mechanical lug is not as high and the quality of the installation is more dependent upon the skill of the installer as compared to installing a compression lug with a dieless hydraulic crimp tool. If you cut through the connector and the wire on a compression termination that was installed with a hydraulic crimp tool, it is hard to tell that the wire was stranded. I guess maybe my preference comes from working mostly on industrial projects when crimp connections are often part of the job specifications.


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