One hole or two hole crimp on lugs

Status
Not open for further replies.
D

Dbronx

Senior Member
Location
Colorado
I have a 800 amp service to terminate and I have the choice of one or two hole lugs. How do you determine the use of one or two hole lugs?
 
It's a matter of preference or design. I prefer two hole but that's twice the labor when installing the bolts.
 
I sometimes use two hole lugs because they stick farther out, but only use the farthest hole. You can sneak another 1 hole lug in there on top of it easier.
 
Two holes will prevent turning on the bus bar and so avoid between phases clearance reducing or contact pad damage. If the bus bar is provided with two holes, [possibility] it is recommended to employ two holes lug.
 
Current Rating

Current Rating

Since the number of holes, 1, 2, or 4, has to do with the contact area, and contact area (all things being equal) translates into contact resistance and heating, you should expect more holes to have a higher current rating for the same temperature rise. In the utility industry, 1200A is often 4-holes and 600A is often 2-holes. There should be a NEMA standard for allowable current rating of 1-hole, 2-hole, and 4-hole NEMA pads or aluminum or copper/bronze.
 
beanland said:
Since the number of holes, 1, 2, or 4, has to do with the contact area, and contact area (all things being equal) translates into contact resistance and heating, you should expect more holes to have a higher current rating for the same temperature rise. In the utility industry, 1200A is often 4-holes and 600A is often 2-holes. There should be a NEMA standard for allowable current rating of 1-hole, 2-hole, and 4-hole NEMA pads or aluminum or copper/bronze.
Click to expand...

UL does that.
 
As far as I know, UL says that the lugs are suitable for the maximum ampacity of the conductor that will fit into the lug, no matter how many holes are in the lug.
 
don_resqcapt19 said:
As far as I know, UL says that the lugs are suitable for the maximum ampacity of the conductor that will fit into the lug, no matter how many holes are in the lug.
Click to expand...

yup.. and a two hole lug can't twist on the bus bar.
i just bought a 2" x 18" bus bar with standoffs for a
data room, and even tho i'm landing #6, two hole
is whats going up.
 
don_resqcapt19 said:
As far as I know, UL says that the lugs are suitable for the maximum ampacity of the conductor that will fit into the lug, no matter how many holes are in the lug.
Click to expand...

That has always been my understanding also. Two holes in lugs are to keep the lugs from rotating.
Burndy makes breakaway lugs that can be either one hole or two hole depending on need.
That being said, I agree with the others. I use the two hole.
 
Status
Not open for further replies.
Top