PDB question for Inspectors

This is a question for those of you who work as inspectors.

We have a tightly packed electronics panel. There is about a one inch gap between the power distribution board and a line of 4-5 motor controllers installed on each side. We have a bundle of PWM wires running through that gap that can obscure the LED’s along the sides of the PDB from being viewed directly. If one of the LED’s is on, we can still see a red glow between the wires. Would this pass inspection or should we re-route the wires now while we still can? The power wires to and from the motor controllers and the snap-action breakers are all clearly visible.

I can post a picture tomorrow evening if necessary.



Visibility of the red ‘open breaker’ lights is not regulated by any rule, nor is it a inspection item. As long as the PDB (including status lights and 24v/12v/5v supply headers) and breakers are easily visible you’re fine from a rules/inspection standpoint.

I agree, we are inspecting for circuit breaker and wire visibility, not those little LEDs.

Of course, imagine you need to replace a motor controller: Can you? If not, you may benefit from some reconfiguration, otherwise you should be OK.

The edge mounted LEDs are really bright and not a problem if you can’t see them direct. Please post a picture, we love to look into other robots.

Thanks for the feedback. We will probably add some cable ties to make the LED’s more visible.

I just posted a link to some photos in another thread.


Those photos don’t look bad to me.

For PWM and other signal routing, I suggest avoiding the neighborhood of high current DC wiring (powerful motors, compressor), or crossing that wiring at right angles. You won’t get dinged for that at inspection, but it improves the reliability of your robot.

One more thing: throw one of these in your toolbox.

While it is best to not mix signal and power wiring, it is difficult, if not impossible to do when wiring devices that have both so one has to follow some common practices used in the Electrical and Electronics industries.

The least coupling that one can get between two wires IS when they cross at right angles. What one should avoid is running “sensitive” wires susceptible to external interference PARALLEL to wires likely to emit interference.