I was wondering the same thing Sparky. I have seen many 100amp Meter pans with one (central) lug. It must have been permitted at one time. Our meterpans on LI even have a separate lug for a bonding wire if necessary.
Bill, When I first started in the trade, the local utility supplied all of the meter cans and they only had one neutral conductor lug, but their rules required that the neutral be continuous from the weatherhead to the service panel, so only one lug was required. Don(resqcapt19)
there was a time that the netural lug was made so you could [should ] do it that way some of you can not rember when the N E C was so smsll that you could cary around in your hip pockrt so your tool pouch would not ride on your hip
In Europe lugs are typically rated for two conductors, but people tend to cram in 3 or more. "Man, those old screw terminal receptacles were far better than the new push-in ones! You could get in up to 4 wires instead of just two!" (that's what an electrician told me 3 years ago). I've even seen breakers with 1.5mm2 solid, stranded, 2.5mm2 solid,... crammed into one lug. Not very sturdy.
And that's what tends to happen here as well. People will just cram conductors in until there's literally no way to squeeze another wire into the bundle. Then they start the "trim off a couple of strands" trick on the larger sizes.