5th Jaw

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George Stolz

George Stolz

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Windsor, CO NEC: 2023
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Hospital Master Electrician
What does a fifth jaw of a meter base do? Does it do something for the meter, or is it just for bonding?

[ September 13, 2005, 08:15 AM: Message edited by: georgestolz ]
 
Re: 5th Jaw

bACK IN THE 60`S OR 70`S IN NYC CON E CHABGED OVER TO 5 JAW TO EEP PEOPLE FROM FLIPPING THIER METERS OVER YURN THEMBACK :eek: tHR NSTEST ONE i SAW WAS A PIN HOLE SIZED DRILL IT WHERE A PAPER CLIP LOCKED THR ROYOR THEBY NO DIA MOVMENT
UNLESS YO GOT INTO REALLY BAD AREAS AND THE METERS WERE ALL N THE FLOOR AMD A EHOLE APT BUILDING WAS JUMPED OUT :eek:
 
Re: 5th Jaw

Around me, 5th jaw sockets are used in downtown locations where they have undergound 120/208 single phase "network services" to the buildings. The 5th jaw is necessary so that the meter head can get the 120V that it needs to read out correctly. I've seen some mobile home parks that have 120/208 services that also require the 5th terminal to be installed in the meter can.
 
Re: 5th Jaw

120/208V "single-phase" services are common in large apartments and offices. These require a 5-jaw socket. The location of the 5th jaw can be at 9-o'clock or 6-o'clock, depending on utility.
 
Re: 5th Jaw

So, the meter wouldn't read accurately without the neutral connection? Would it over- or under-read?

Is it only useful in 120/208 applications?
Is it only useful in 120/208 1? (derived)?
Why have utilities around here required them for 120/240 1? services? :)
 
Re: 5th Jaw

Nope didn`t have my caffine fix at the time but cut that 5th jaws neutral and see what happens.
Idid it there will be a test on thursday :eek:
 
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