petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- Semi-retired engineer
670.6 Surge Protection. Industrial machinery with safety
interlock circuits shall have surge protection installed.
I wonder what this means in practice.
Is surge protection at the service acceptable?
How about at the main disconnect/OCPD for the machine?
Or is it asking for surge protection on the safety circuits themselves, or at least the power to them.
And what do they mean by safety interlock circuits.
Note that it does not require a surge protection device, only surge protection. Most DC power supplies these days have some kind of surge protection built in. if the requirement is for the safety circuits themselves to have surge protection wouldn't the power supply already provide that?