Switch box - reason to select metal or plastic?

[Chris Barnett]

Am finishing my rounter cabinet [been gathering parts/materials lets say, years] and want to know if there is a reason to use plastic instead of metal switch boxes, or vice-versa. Have metal but I read on a posting here that plastic should be used. The second means just another trip to the store [the last?] but another delay.

All that is left now is to install dust collector fittings and then switches on each end with the master on the back. Added the L/R end emergency switches with kneeable large flat on/off buttons, as several folks recommended in other posts. These are the modern flat wall switches that were the rage in the 50's or so, not the red and green ones normally seen with the large paddle stop. These will be in series with the master to permit any of the three switches to shut the motor off. Any one know a reason not to do it this way? I am a little concerned with having a switch box projecting into the cavity that contains the router/motor since the boxes are not dustproof, but otherwise ok.

So plastic or metal switch boxes, and other comments? Thanks for any help.

[Charlie Velasquez]

Plastic doesn't have to be grounded, saves you a pigtail.

[Andrew Pitonyak]

Adding myself to be copied so that when the electricians pipe in, I will see what they write.

Question: Does your box somehow connect to a shielded system where you might want the box to be grounded so that it can then be used as a ground? if not, my totally uninformed (and therefore dangerous opinion) is that it would not matter.

I assume that a metal box will deal with an internal fire better.

[Ken Fitzgerald]

The switch I ordered for my router table came with plastic box.

Plastic...you don't have to worry about something shorting out on the box itself.

[Wade Lippman]

Plastic or metal is your choice; I like plastic. Metal ought to be grounded through the switch automatically.
Why do you want to put 3 switches in series? I don't see any reason why it should be dangerous, just awkward.
On the two router tables I have made I surface mounted the boxes, so dust was not an issue; but sure, dust could easily cause the switch to work poorly.

[Chris Barnett]

The power supply is two wire with ground; I plan to continue the ground wire separate from neutral unless advised otherwise, and ground would be connected to the box if metal. Don't know if this answers your question. I don't see an advantage to a metal box other than, as said, higher resistance to fire and perhaps stronger, depending on the plastic. I do prefer the adjustable cable clamps on the metal box and believe they are kinder to the cable. If polycarbonate [lexan], I would prefer the plastic.
If your comment regarding a shield is asking about RF interference, no, I have not given that any thought. I could add screen to the inside surface of the sides and bottom, but have not heard of a router causing a problem.

Regarding the dust issue, I expect there is insufficient volume to be a major concern and will mount the boxes as planned.

[Larry Browning]

Your over thinking this, just go with what ya got! Either one will be safe and durable.

[Chris Padilla]

I like metal...the threads don't strip so easily like they can in plastic plus I just like the robustness.

[Chris Padilla]

Why do you want to put 3 switches in series? I don't see any reason why it should be dangerous, just awkward.

I assume the OP is putting in 2 3-way and 1 4-way switch? On my router table, I did exactly this so that no matter where I am in position on the router table, I can easily flip the closest switch to shut it off. Since the 4-way is the pricier one, I mounted that in the spot I felt I would least likely use it so that the cheaper 3-ways get the majority of work.

[Stephen Cherry]

A grounded metal box in contact with a loose conductor will carry the juice to ground and trip the breaker.