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Old November 18th, 2010   #2
ericthegeek
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Join Date: Aug 2008
Posts: 355
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> I was wondering how electrical safety is
> defined for the DMX bus?

It's not defined. None of the ESTA standards directly address safety. Safety is the domain of a company's lawyers and compliance engineer.

You may want to read the two cabling standards, they might give you some ideas to consider. Also look at the various topologies defined in E1.11, as well at the enhanced common mode section.

> The DMX wires are not insulated, meaning that
> they can be touched at least at the connectors.

Over a long cable run you can build up a substantial ground potential difference. Also, an equipment fault elsewhere in the system can put line voltage (or worse) on to the DMX wires.

It is a common practice to galvanicly isolate the DMX port from the rest of the system. This can provide some protection, but how much protection you promise is a matter for the lawyers.
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