Relay Replacement on MetalClad Switchgear (Existing Doors vs New)

[rockman7892]

I've looked at a few relay replacement projects recently on MV Metaclad switchgear where customer wants to either replace existing electromechanical or antiquated microprocessor relay with upgraded microprocessor relay.

There always seems to be a back and forth decision on each of these on weather to provide new relay cutouts on existing doors vs replacing the doors (Pros and Cons to each). To me it has always been more straight forward and less costly to modify cut-outs on existing doors than have to match and purchase new doors (correct hinges etc...)

To me if the end user does not care about the cosmetics of having filler plates and blank plates to cover old relay cut-outs and there is enough room to have new relays and devices (Test switches etc..) this always seemed to be the more cost effective route (especially when there are a bunch of existing control devices on door that will be re-used with new relay).

I have heard a lot of electrician's and relay tech's make the argument that cutting of existing doors in the filed is sometimes not easily feasible (especially with metal filings getting airborne) and say that having a new door to plug and play with (and have to re-connect wiring) is a much cleaner solution.

Looking for feedback and any lessons learned from either approach.

Thanks

 

[mparenteau]

Landed on always using the new door approach. Less time for connects in the field, etc.

Mike

PS I haven't had a negative experience with either option.

 

[Sn00ze]

I've never replaced the door, only made a cut big enough for a cut out already with relay mounted. but the TBs were inside of switchgear. i think if you can fabricate everything on the door it may be more cost effective (less field time wiring) but if the TBs are inside of the enclosure you probably wont get much savings.

 

[thermionic1]

If you are doing one or two and don't care about the appearance keeping the existing door is cost effective. You really should remove all the wiring from the existing relays or you are waiting for a mis-op to occur.

Any more than 3, have the panel/door builder come out a take measurements - it's on them to make it work. Especially if outage time is critical, this is WAY quicker. The relay can be set and tested ahead of time with VT/CT & trips checked after install. I've worked on projects where this was the MOP and we would have a feeder swapped over in less than 4 hours.

 

[TesterRon]

I have recently completed 2 Substation line ups replacing GE Multilins with SEL relays. The old relays had no test switches, the SEL's were physically smaller than the GE's. Had custom powder coated plates made locally with test switch cutouts added. These were surprisingly cheap, and with the manufacturers provided templates very precise fits. Had the relays and test switches mounted, pre-wired from the TS to the relay, relays programmed, and tested before the outage. On outage day we unwired and removed the old relay, enlarged the opening with a jigsaw with a vacuum attachment for metal shaving containment. Landed the existing PT's and CT's to the bottom of the new test switch, and re-terminated all of the existing control circuit wiring. Breaker and control circuits were verified in the test position.

The first one or two were a full days work, but not bad at all. Myself and a Journeyman wireman could easily do 2 a day now, but the customer is happy with 1 a day. One circuit out at a time and the plant keeps running with no Bus outage.

 

[wcaseyharman]

Have done both. Pros and cons to both. More design and fabrication for new doors and some additional risk if it doesn’t fit, but tends to allow for more pre-wiring, faster swap out and a better looking product when it’s done. I’ve had more stress on the doors fitting correctly than any of the electrical design.

 

[bwen08]

We've never bought new doors, always used filler panels or patch panels. The last one we actually had a local waterjet company do all the cutouts on stainless steel sheets that were a tad smaller than the door dimensions, removed the door to bring into the shop, enlarged holes on the door to provide room for the new equipment and riveted the sheets onto the door. We were happy with the process and finish look so that is likely what we'll continue to do.

 

[Gr8blu]

NOTE - If the gear is classed as "arc resistant", you are REQUIRED to use a new door to maintain the system integrity and classification.

Converting energy to motion for more than half a century

 

[cranky108]

I don't think so, for arc-resistant gear. Well maybe. In some arc-resistant gear the door for the controls is not part of the arc-resistance. Only the door for the breaker is arc-resistant.