RE: [CAD_CAM_EDM_DRO] Re: electrical code?

The grounding of your house's electrical system is done near your service
switch. This ground is carried through your electrical system to your local
outlet (or safety switch/motor starter if you have a larger machine). On a
well designed commercial controller, the manufacturer is presumed to have
been careful about making sure it is properly grounded. The reason for my
emphasis is that if you are designing your own unit, you may inadvertently
be isolating some electrically active components from others. IF YOU USE
PLASTIC WASHERS OR FACEPLATES AND MOUNT STUFF TO IT, YOU MAY HAVE AN ISUUE.
If your machine is not bonded to your controller, you are looking for
trouble if something malfunctions.

A bonding jumper is simply a piece of wire (traditionally with green
insulation) which is connected to two pieces of equipment to make sure they
are at the same ground level. Depending on the situation, a bolt generally
holds a lug on each end of the jumper to the metal chassis or machine.

If different parts of your system are at different ground levels (poor
grounding) it can destroy electronics and/or create a safety hazard for the
operator.

Rather than going on at too much length, (we're getting a little off topic
here) feel free to contact me off list if you need specific advice.

Regards,
Jeff

-----Original Message-----
From: andrewyslee [mailto:andrewlee@...]
Sent: Thursday, April 17, 2003 7:04 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] Re: electrical code?

"Jeff Goldberg" <jeff@w...> wrote:

> Grounding, grounding, grounding! Make sure all your metal

components are

> bolted together.

Will help to understand WHY. Most of the electrical boxes I have open
seem to have only one point earthed. I don't see any wires connecting
all the metal parts together. Probably I haven't open enough boxes.

> If the bolts are over paint, put in bonding jumpers. Make
> sure your machine is bonded to your control cabinet. Make sure
> your D.C.
> negatives are all grounded.

What is a bonding jumper? Are they just simple wires meant to connect
metal parts together?

Thanks

Andrew



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