Metal Electrical Board

[aaeamdar]

I know that the "proper" forum in which to post this question is the FIRST Q & A Forum, but considering that my un-scientific sampling tells me that we can expect to wait at least two days (which would be too late) to hear a reply to our question, I'm going to re-post this here.

Our electrical board is made out of metal. We were told at a playday by someone who said he would be inspecting at Chesepeake that this was really not a good idea and the inference was that it could pose a hazard (to our robot passing inspection)*. The suggestion was that we replace the boards with a non-conductive material. We are not eager to do this, as it would involve many hours worth of work at a time when we're already very busy. We proposed to this inspector that some sort of insulator be put between the top and the bottom boards (we've split them in twain), and he seemed to find this acceptable. However, since the boards are not electrically isolated from each other, this seems rather like putting a water-resistant material on your thigh and thinking that you are protected from the rain. Namely, it will do little to assuage the problem (if there is one).

I already know about R51, and I've checked the resistance between pretty much every component and the chassis. My question is, if we PASS R51, could the inspectors still fail us and if so, how?

Thanks,
Paul Dennis
Team 1719


*I'm getting a report of this conversation second-hand, so I really cannot be specific as to a) who this person was and b) what they said.


P.S.: I'm not asking if this was a good idea, just whether it's legal. Helpful advice is still appreciated, of course.

[EricH]

There are no limits to what you can use as an electrical board.
(Q&A--see answer)

However, you can't ground to your frame/robot.

What I'd do is insulate every connection on the board--with two or three layers--so that there is no chance of grounding to the robot.

If you pass all the rules and an inspector fails you, talk to the head inspector.

[thefro526]

According to R51 - All wiring and electrical devices shall be electrically isolated from the ROBOT frame; the
ROBOT frame must not be used to carry electrical current (this isolated ground arrangement
is necessary due to polarity reversals that occur under certain operating conditions such as
during motor direction reversals).

As long as this is satisfied then your board should be legal. I would suggest changing you board to some non-conductive material just to be safe for competition and inspection.

[Racer26]

1075 has used i think .015" thick aluminum for our electrical panel for 5 years running, and never had any trouble due to that at inspection. You'll be fine.

On another note, I wouldn't want to use any metal other than .015" alum for the board, purely for weight reasons.