Electrical Safety requirements for DMX / RDM lines - E1.20 RDM (Remote Device Management) Protocol Forums

R.Schladör · November 18th, 2010

Hi all!

I was wondering how electrical safety is defined for the DMX bus?
The DMX wires are not insulated, meaning that they can be touched at least at the connectors.

Are there any considerations for electrical safety that I need to think of for my devices?
Or are there any additional safety-standards that DMX devices need to comply with?

How do you address this topic in your products?

ericthegeek · November 18th, 2010

> 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.

November 18th, 2010	#1
R.Schladör Junior Member Join Date: Oct 2010 Posts: 2	Electrical Safety requirements for DMX / RDM lines Hi all! I was wondering how electrical safety is defined for the DMX bus? The DMX wires are not insulated, meaning that they can be touched at least at the connectors. Are there any considerations for electrical safety that I need to think of for my devices? Or are there any additional safety-standards that DMX devices need to comply with? How do you address this topic in your products?

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November 18th, 2010	#2
ericthegeek Task Group Member Join Date: Aug 2008 Posts: 383	> 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.