Estimating removal and installation of switchgear

[philly]

We get involved with a lot of switchgear removal and installation projects. Although I mainly support engineering functions on these projects I do find myself from time to time getting involved with determining schedule and estimating for construction labor for removing and installing switchgear lineups.

I realize depending on the switchgear and application there is not a once size fits all answer here but was looking for more of a high level approach that others have seen or used. For example:

• "X" number of man hours to remove or install (1) section in a multi-section lineup?
• "X" number of man hours to de-term and re-term existing feeder cables
• "X" number of hours for control wire terminations

I appreciate any rough high level thoughts or experience here.

 

[hillbilly1]

Are these same for same? Or newer models? I never get any easy same for same! Usually the one being removed is obsolete, and the new is designed totally different, so trying to make it match can be time consuming. Lug placement and other factors contribute to labor costs, whether to extend and splice, or repull completely. I have a 75 kva transformer changeout coming up, the old transformer is no longer made (2006) the new has the lugs 16” higher. Modular built gear and enclosures.

 

[sameguy]

Are these same for same? Or newer models? I never get any easy same for same! Usually the one being removed is obsolete, and the new is designed totally different, so trying to make it match can be time consuming. Lug placement and other factors contribute to labor costs, whether to extend and splice, or repull completely. I have a 75 kva transformer changeout coming up, the old transformer is no longer made (2006) the new has the lugs 16” higher. Modular built gear and enclosures.

Did you check with manufacturer to see if they can modify HB1 ?

 

[hillbilly1]

Did you check with manufacturer to see if they can modify HB1 ?

I’ve had good luck with Square D modifying enclosure sizes to fit, not so old Eaton transferswitches would have tight grouping that wouldn’t fit in the same window as Square D, the factory would build longer enclosure’s to fit. One of our competitors didn’t take that into account, and when they shut the store down, and yanked out the old switch, they found out it wouldn’t fit! Too late! Customer was not happy! Utility and generator connections were usually opposite too, even on the smaller 600 amp sizes.

 

[paulengr]

Schneider is getting dry transformers from MGM. Just go to someone else to order because SqD engineering is a pain.

 

[hillbilly1]

The good thing is, the enclosure is rather large, so shoehorning it in is not a big deal. Walmart stacks their transformers on top of refrigeration equipment in the roof top shacks. The manufacture of the shack cut the legs off to fit. The new high efficiency ones are much taller, and when you only had 3-4” between the top and the roof, a 8” taller one will not fit! LOL!

 

[paulengr]

As far as OP, WAY too many variables to simplify it that much. If you want a guess look at NECA MLU but for instance I’m working on a250 HP VFD fully self contained with disconnect, keypads, etc. We’ve done them in one day. This one is taking 3 days. Lots of work on the wiring, finessing EMT, etc. All add to the time involved. And why you always try to estimate high or have a lot of missed quotes.

 

[philly]

As far as OP, WAY too many variables to simplify it that much. If you want a guess look at NECA MLU but for instance I’m working on a250 HP VFD fully self contained with disconnect, keypads, etc. We’ve done them in one day. This one is taking 3 days. Lots of work on the wiring, finessing EMT, etc. All add to the time involved. And why you always try to estimate high or have a lot of missed quotes.

Yes understood that there are way too much to simply here. Lets say we make the following assumptions just for the same of ballparking man hour estimates:

- MV M-T-M metalclad switchgear with (10) sections. All sections to be removed and discarded.
-There are no access issues with roll-up doors in room to get fork-lift in and out to remove sections. Crane access outside room.
-New switchgear fits exact same footprint as existing
-All existing MV cables will be de-terminated from existing gear and re-terminated on new gear. No labor for new terminations.
-All existing control wiring will be de-terminated from existing gear and re-terminated on new gear. Assume (10) control cables per section for misc control etc...
-Any other general assumptions worth considering here?

Again just trying to understand approach or philosophy here and not necessarily concerned with trying to pin down a number.

 

[hillbilly1]

Never messed with MV, but if it’s like low voltage (<600 volts) the manufacture changes everything around, termination heights, locations, etc. just replaced a 15 year old 75 kva transformer last week, same manufacture. A and C phase was opposite, lugs were 8” higher. The past 15-20 transferswitchs I’ve changed out, the normal and generator sources have been opposite. So I would make sure the manufacture is building same for same before I wrote off “no labor” on existing terminations.

 

[paulengr]

Looking at about a day and 2-3 head to mark and unwire and pull back everything, hopefully a day to disassemble and remove. I’d say one day for all of this if not for the number of sections. Usually we knock this all out on the first day unless there are complications like difficult access.

At this point you want to dowel in rebar, form, and pour any base modifications with high early strength concrete so that it has overnight to set.

Then a day to put the new stuff in, again 2-3 head. After this looking at about 4 hours per section to land wiring and terminate for say 4/0 or smaller and it gets up to about a day for multiple 500s with 1-2 per section. Then figure in your labor with multiple sections. If it’s just landing wires sure you can do it in a couple hours but if you have to splice, cut, and/or rework terminations you can quickly turn this into an hour per cable, assuming you have lugs and cold shrink or tape termination kits on hand. Trust me, you ALWAYS have to at a minimum redo a few terminations where the silicone cracks and starts peeling back.

One man, one day to set up relays. Mostly the two mains, the tie (if it’s separate), and the feeders are your three sets of settings. Everything else is copy/paste and change things like the tap for long term tripping.

Two men one day if you are doing extensive NETA style acceptance testing. If you are just going to Megger then don’t count this at all.

Two men one day for commissioning/startup, assuming the plant doesn’t slow you down. When they take an hour or two per breaker test it can get obnoxiously long.

Two men half a day for cleanup.

This is assuming experienced labor. In all honesty the number of sections doesn’t matter that much. It’s all in the issues you run into and if you can flex up the labor on wiring then downgrade to normal at the beginning and end. Most of the time these things take about a week, maybe two with a truly big system.

Keep in mind a lot depends on the condition of the original equipment too. If it’s structurally in rough shape just replace. But if breakers or equipment are available, refurbishment or retrofit/retrofill is a lot more economical. It could be a simple matter of swapping out say old with new or making doors with new relays and simply swapping out all the old induction disc units with microprocessor relays. There are some breaker designs that are inherently awful and others where it’s just lack of maintenance and old electronics that are the limiting factors.

 

[philly]

Looking at about a day and 2-3 head to mark and unwire and pull back everything, hopefully a day to disassemble and remove. I’d say one day for all of this if not for the number of sections. Usually we knock this all out on the first day unless there are complications like difficult access.

At this point you want to dowel in rebar, form, and pour any base modifications with high early strength concrete so that it has overnight to set.

Then a day to put the new stuff in, again 2-3 head. After this looking at about 4 hours per section to land wiring and terminate for say 4/0 or smaller and it gets up to about a day for multiple 500s with 1-2 per section. Then figure in your labor with multiple sections. If it’s just landing wires sure you can do it in a couple hours but if you have to splice, cut, and/or rework terminations you can quickly turn this into an hour per cable, assuming you have lugs and cold shrink or tape termination kits on hand. Trust me, you ALWAYS have to at a minimum redo a few terminations where the silicone cracks and starts peeling back.

One man, one day to set up relays. Mostly the two mains, the tie (if it’s separate), and the feeders are your three sets of settings. Everything else is copy/paste and change things like the tap for long term tripping.

Two men one day if you are doing extensive NETA style acceptance testing. If you are just going to Megger then don’t count this at all.

Two men one day for commissioning/startup, assuming the plant doesn’t slow you down. When they take an hour or two per breaker test it can get obnoxiously long.

Two men half a day for cleanup.

This is assuming experienced labor. In all honesty the number of sections doesn’t matter that much. It’s all in the issues you run into and if you can flex up the labor on wiring then downgrade to normal at the beginning and end. Most of the time these things take about a week, maybe two with a truly big system.

Keep in mind a lot depends on the condition of the original equipment too. If it’s structurally in rough shape just replace. But if breakers or equipment are available, refurbishment or retrofit/retrofill is a lot more economical. It could be a simple matter of swapping out say old with new or making doors with new relays and simply swapping out all the old induction disc units with microprocessor relays. There are some breaker designs that are inherently awful and others where it’s just lack of maintenance and old electronics that are the limiting factors.

Thanks this is helpful. From what I've seen in the past its mostly been about a week duration to replace gear I was curious though on how others approached it in terms of man power.

 

[paulengr]

Thanks this is helpful. From what I've seen in the past its mostly been about a week duration to replace gear I was curious though on how others approached it in terms of man power.

As we keep saying it’s all in the details.

A couple years ago had a “simple” fused disconnect feeding a switchboard with about a dozen breakers. Simple 2-4 day job right? Man did this one blow up into a week long ordeal.

To begin with the HVAC duct monkeys caused all kinds of grief. Had to split the outgoing couplings to slide the conduits apart and loosen the wiring to remove old conduits. No comment about NEC requirement not to add/remove conduit with wiring already inside.

Then after removal we found they left just enough space where everything was about 2” short of going under duct and up onto pedestal. We ended up disassembling all the cabinet sides but one and removing some framing then maneuvering what was left with cabinet jacks into place. Had to use old cabinet top as a template to do conduit cutouts then slide about a dozen conduits in it, then disassemble side of switchboard and drive it into place under top panel. This was just to mount it all.

Then came tons of swearing running the 8/C 500 MCM feeders (don’t ask why when the transformer was 1500 kVA), which were all cut as short as they possibly could off the duct banks. Then more swearing and hiring an apprentice that was skinny enough to snake in behind the switchboard and pull all the cables through to land them.

For an easy 2 section job...

 

[don_resqcapt19]

Thanks this is helpful. From what I've seen in the past its mostly been about a week duration to replace gear I was curious though on how others approached it in terms of man power.

If everything is bottom fed, and there is enough room to lift the gear up over the conductors, I would probably look at 4 to 6 guys for two 12 hour days for that.

If it is top fed, everything changes...you then have to pull back the conductors and remove the conduit, then reverse that for the new equipment....now looking at closer to a week.