Hey Joe, what would you happen to know the wire gauge equivalent of a number two Phillips screwdriver? This was found during an investigation of electrical usage on a meter that had been "booted". The suspect went through the utility section and inserted the screwdrivers behind the meter without pulling the meter. One of the plastic insulators was damaged and allowed the meter to register use, which caused the investigation and discovery. The remnants of one of the insulators can be seen in the lower right meter clip.

133.2 Ohms for a 1/4" dia steel screwdriver shaft placed between 4" apart tabs.

R=p l/A R=Resistance p= specific resistance for material - steel is 100 l=Length A=Area in Kcmils

R=100 (.333/.250)

Of course, I had to really dig around to find this one...never had to use that formula before. I'm probably wrong, but it killed some time, and fired up the brain cells... good post!

Re: Ampacity of a #2 Phillips?#116647 04/16/0406:03 AM04/16/0406:03 AM

Can't belive someone actually tried to answer the question!

Nice try but there must be something wrong with that calculation. Probably a decimal point somewhere. I think the resistance of steel is approximately ten times that of copper. This (I think) means that you should move ten sizes AWG to get the equivalent copper screwdriwer. Remeber to use only a listed electricians screwdriver for this. Come to think of it, I haven't seen any of those lately...

If the diameter is 1/4" the area is roughly 30 mm2 (note my systematic use of units) or approx 2 AWG. Thus, the ampacity is similar to that of a 12 AWG copper conductor.

Somebody, please correct this!

Re: Ampacity of a #2 Phillips?#116648 04/16/0406:37 AM04/16/0406:37 AM

When the area is expressed in Kcmils, and the length is expressed in _1000 feet_, K for copper is something like 10 or 12 (depends on temperature and the reference that you are looking at). I'll trust you that the K for steel is 100; for iron it is about 50, but for different steels it can be all over the place.

Area in circular mils is the diameter in mils _squared_.

So we get: area = 250^2 = 62.5Kcmil length= 4 inches /12000 inches = 3.3333*10^-4 Kfeet