Plastic vs. Metal Boxes

Status
Not open for further replies.
JOHNEO99

JOHNEO99

Senior Member
Location
Northern Illinois
Hi

Im doing a job in an area that is mostly done using emt and not romex. This is a residential job and the builder has been trying to cut costs to induce sales. The local building department has just started to allow romex in their village and we are changing from pipe to romex. The village allows plastic boxes but for some reason (I'm not sure what it is) the builder wants me to use the same metal boxes that we use when piping these homes.

I believe they are worried about the integrity/long term durability of the plastic boxes vs. the metal. I disagree that the plastic boxes are a risk to this factor and I really want to use the plastic boxes for obvious reasons.

Can some of you people give me some reasons as to why plastic is as good or better than metal when installing romex?

I think the opinion of this community should help me with my agenda here.

Thanks

John
 
Cavie

Cavie

Senior Member
Location
SW Florida
Maybe someone here will post a pic of a mega$$$$ million house being roughed in romex with plastic boxes for you to show how it's done.
 
ceb58

ceb58

Senior Member
Location
Raeford, NC
Power Tech said:
The plastic boxes have a 1 hour fire rating.

They are deeper.

Less cost.

Less work.
Click to expand...

All of the above.
With the box in a wall covered with Sheetrock/ paneling they are not subject to damage. Try this with your GC buy a carlon plastic box, nail it to a stud just like it is supposed to be. Then give the GC a hammer and tell him to beat the box off the stud. He will after several swings break the box off but then ask him if he thinks that box will see that kind of abuse inside of the wall.
 
D

dejeud

Member
This has to be the easiest answer.
Three words:
Resistance to change.
Could be also 2 words if you don't think "to" should count as a word, but anyway.
Humans are always resistant to change, or afraid of change. In either case, there's something about humans that don't want to change, be it food, clothes, or Aluminium wire.
Speaking of AL, I think it's the best example to people resistance to change.
Look at AL wire, now I know the old AL used to be too soft therefore the connection got loose with time and so on and so forth, BUT:
1: In my 7 years doing service I found just as many AL connections being cooked as I found Copper. And this is based on probably MORE AL connections than Copper.
2: The new AL is not as soft as the old AL, so even the need of "lollipops" has been eliminated.

Now consider the advantages of AL wire:
1: It's the second largest resource on earth after Iron (or 3rd if you consider Oxygen a resource)
2: AL has lower ampacity by volume, but much higher by weight. Guess what, you buy the wire basically by weight, therefore the price doesn't even begin to compare.
3: The difference of ampacity between Copper and AL are almost insignificant, most of the times you'd only have to go one size larger to match ampacity of copper.
4: Even going a size larger, doesn't always mean you have to increase conduit size. Check the size of 700XHHW AL VS 600 copper and you'll be surprised to learn that the AL is almost same size. Now look at weight per 1000' Copper is almost double than the one size up AL, now figure $3/lbs for 2000' of copper VS $1/lbs for 1000 lbs of AL. $ 6000 VS $ $1000. No brainer? right? guess not.
5: Because the weight AL is a hell ov a lot easier to pull than copper.

So why isn't the whole world sold on AL? (least for feeder wires?). If it's not resistance to change I don't know what it is.


JOHNEO99 said:
Hi

Im doing a job in an area that is mostly done using emt and not romex. This is a residential job and the builder has been trying to cut costs to induce sales. The local building department has just started to allow romex in their village and we are changing from pipe to romex. The village allows plastic boxes but for some reason (I'm not sure what it is) the builder wants me to use the same metal boxes that we use when piping these homes.

I believe they are worried about the integrity/long term durability of the plastic boxes vs. the metal. I disagree that the plastic boxes are a risk to this factor and I really want to use the plastic boxes for obvious reasons.

Can some of you people give me some reasons as to why plastic is as good or better than metal when installing romex?

I think the opinion of this community should help me with my agenda here.

Thanks

John
Click to expand...
 
M

macmikeman

Senior Member
Location
Planet macmikeman
I bet that same GC puts in Pergo floors. I bet he uses Tyvek instead of roofing paper to moisture seal in the house. I bet he uses a nail gun cause it is faster. I bet he doesn't even own a handsaw. I bet he cools his house in summer with air conditioning, not meerly opening up windows. I bet he doesn't fill his tank with leaded gasoline. I bet he was the last one to try all those things.....
 
A

AV ELECTRIC

Senior Member
You dont have to bond the box as you would with metal. plastic is non conductive cant be electrified. Does not corrode. Ive seen moister get to metal boxes and they decay over time.
 
LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
JOHNEO99 said:
Can some of you people give me some reasons as to why plastic is as good or better than metal when installing romex?
Click to expand...
If he's that closed-minded about it, he'll ignore all the reasoning in the world.

I suggest offering him the cost for using each type of box, and let him decide.

If he's willing to pay more for you to continue use of the metal boxes, so be it.
 
P

Power Tech

Senior Member
Location
Lebec, California
In some situations (back to back switch in wood) I use metal so the switch is not too far from the door. Customer ends up with a dirty mark on the wall.

I would accommodate too. Be generous with the deep boxes.

I would use the plastic if there is a fire envelope. You can pad the metal boxes with clay instead. May be a few cents more.;)
 
M

mkgrady

Senior Member
Location
Massachusetts
JOHNEO99 said:
Can some of you people give me some reasons as to why plastic is as good or better than metal when installing romex?
Click to expand...

What is his reason why metal is better? I doubt he has a valid one.

If you use plastic you will save way more than the price difference between box types.
 
kbsparky

kbsparky

Senior Member
Location
Delmarva, USA
Plastic boxes don't rust. :grin:

They can't short out on a bare piece of wire, or loose terminal.

You won't have to buy any green screws, either.

We did a job once where we had to remove all the rusted out metal boxes, and reinstall plastic ones. 20 years later, those plastic boxes are still in use.
 
marti smith

marti smith

Senior Member
You could always ask him if he'd like to install one of each himself and see what he thinks (you don't give him a drill, just a flathead- oh, even better, an offset flathead) and be sure to give him two 2-screw romex connectors and a grounding pigtail. That should set him straight.
 
2

220/221

Senior Member
Location
AZ
Simple.

Plastic boxes are safer in NM applications because they are non conductive just like the sheath on the cable. They were engineered and designed decades ago especically for use with NM.


The fact that they are easier and less expensive is a bonus brought on by supply and demand.
 
Status
Not open for further replies.
Top