well....we can look at this in terms of usage, location, durability ,callbacks, etc. myself i use a mix of the two.
but probably the most common approach is time, and time is a bid winner.
one metal CON i did notice recently was that the old work metal box ears screws protruded into the box about 1/16". This was just enough to prevent a rotary timer and some dimmers to enter, had to get the dremmel out...
Re: Metal or Plastic?#1134 04/28/0110:30 PM04/28/0110:30 PM
Metal boxes, Metal conduit, Taped Receptacles with Ground up.
Metal conduit system for secure installation. Taped Receptacle sides in case someone desides to pull a live Receptacle out of the box. Ground up in case something metallic falls down onto the inserted plug [will not help for 2 wire plugs, though].
One other thought - A person could easilly have an IG circuit by using 12/2 Romex and non-metallic boxes. I'm sure this is not new to many people, but it is to me!
Let the Flames Begin!!
Scott " 35 " Thompson Just Say NO To Green Eggs And Ham!
Re: Metal or Plastic?#1135 04/29/0112:16 AM04/29/0112:16 AM
I was trained with metal boxes, even in residential. We'd pigtail an EGC to a green screw, crimp it down with a PT-70M barrel crimp, and strategically place the sharp pointy mess in an unused corner of the box. Very labor intensive.
Just mounting the box plumb and square required drilling recesses for the jutting screws on the box sides. Only then would we finally nail the box to the stud.
Remove the unused loom clamp to save on wire count, and we used CXW's (3 1/2" deep) unless at the end of a run.
BTW we NEVER used #14 wire, even on 15A protected lighting circuits.
Metal staples were the only thing available at the time, I've since been able to somewhat aquire plastic cable straps, which a far superior. (Specially stocked for Musser Electric and Kelly Electric, the two past apprentices of my old boss.)
I use plastic Carlon boxes now, and I'll use PVC every time the situation permits. Less bonding /grounding issues to worry about.
Bill has me almost convinced to use #14 wire on my next rough in...appropriately, of course. But I digress again...
-Virgil Residential/Commercial Inspector 5 Star Inspections Member IAEI
Re: Metal or Plastic?#1136 04/29/0101:19 AM04/29/0101:19 AM
BTW, removing the extra clamp does not save your wire count according to 370-16(b)(2) The deduction taken is for 1 or more cable clamps within the box.
I'm a big Carlon fan myself. It makes things much easier. Boxes are more roomy and non-conductive so less labor involved (no bonding)
As far as the #14 goes, In order to get work you sometimes have to bid the jobs like everyone else does and then give the customer the opportunity to upgrade a notch. Lately I've been very aware of instances where this minimum requirement (#14) has been abused by very long runs and excessive voltage drops. I would recommend using #12 for these feeders.
Re: Metal or Plastic?#1137 04/29/0101:42 AM04/29/0101:42 AM
i have to agree with scott on this one.. for all new construction, and where ever possible, we use metal 1900 boxes, piped in, devices taped... when we have to fish things in, depending on the situation, we'll use romex, MC, or greenfeild.. we like to use raceway as much as possible, just incase the custormer changes their mind.. we hardly ever use smurf either.. pullin in that extra ground.. more material waste etc..
Remember when you read my posts, im only 17, still learning... "Hey, its takes what it takes!"
Re: Metal or Plastic?#1139 04/29/0110:45 AM04/29/0110:45 AM
For residential- plastic, unless you don't want to get the job. I've had very little trouble with plastic boxes.
Commercial- such as offices- depends on the depth of the customers checking account. If the job is so tight that I have to use non-metallic cable, I use plastic boxes. If they can afford to upgrade to MC cable, obviously this gets a metal box.
Few things are harder to put up with than the annoyance of a good example.
Re: Metal or Plastic?#1141 04/30/0103:48 PM04/30/0103:48 PM