What is Maintenance Mode? (MMS, ERMS, ARMS, RELT, DAS)

[@obrigadoamigo]

I don't comment on many videos but yours are fantastic and always cover all of my questions. Thank you!

[@testingtechtips]

I appreciate that and I'm glad to help!

[@davidwhelan8550]

For a guy that claims "I am not an engineer", you ably prove that you don't have to be to be engaged in your craft. great job.

[@testingtechtips]

Haha thanks, I mostly use it as a caveat in case I get the facts wrong. (The comment section is always smarter than I am!)

[@mattprombo9691]

Thank you for the detailed content Joel! There are very few people discussing this information and passionate enough to take time to share.

[@testingtechtips]

Glad it was helpful! I've learned more about my job from KZbin than I care to admit so I'm just trying to make it easier for more guys in the same boat.

[@mattprombo9691]

Greatly appreciate it and I hear you on learning from KZbin. It's a great resource for learning for self motivated and curious people.@@testingtechtips

[@aroncells3120]

Thank you for a very detailed explanation on this topic

[@testingtechtips]

Yeah it's hard to get a full grip of maintenance mode in general since so many sources only give you little bits of info for a single system.

[@southernstaffing]

Great insights Joel!!!

[@testingtechtips]

Thanks! I appreciate the support!

[@mahamhaider3301]

thank you!

[@testingtechtips]

You're welcome! Thanks for watching

[@stefanhermannsson3765]

For s Siemens system, do we need to disconnect the load side conductors of the breaker for arc flash reduction switch testing?

[@testingtechtips]

It depends how you're testing it and if you've properly isolated the system upstream.

[@carlaaccioly885]

Hi in our substation , we have this switch in the incomers and tie and also in the mcc outgoings. But not in the triristor and feeders outgoings. Could you help me understand why some outgoings has this switch and other not?

[@testingtechtips]

Man I'm sorry but I don't have anywhere near enough detail on your specific application to help you with that one.

[@bobandi19]

why doesn't the requirement apply to industrial facilities?

[@testingtechtips]

I chose my words poorly. There is nothing inherently different between "commercial" and "industrial" according to NEC and so 240.87 technically would apply to industrial facilities with equipment over 1200A. In speaking generally, a facility with a medium voltage service will (typically) have a relay and fast enough breaker or some other means to limit the arcing current, meaning maintenance mode isn't (typically) relevant for heavy industry.

[@indiansupporter3822]

No that is not correct Arcing current is not 40 percent of bolted fault current, Arcing current percentage variation depend upon the k factor which is computed by taking into account the electrode configuration and other factors reference ieee 1584 2018

[@testingtechtips]

I have to go off the few sources I've read including NFPA 70E D.3.1 which calls out the "industry accepted minimum" arcing current as 38% of bolted fault current. I preface that oversimplification by stating I'm not an engineer because it's absolutely not my area of expertise and is clearly not a key takeaway from this video.