Demo/ Safe-Off Power

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Alwayslearningelec

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Estimator
Hello All

Have a 20 story building that is being demo'ed inside.
They want electrician to tag/safe-off/disconnect power. I would qualify we are not disconnecting but tagging and safe-off.

What would involved/process for the electricians to accomplish this?
They give us existing riser and there are bunch of distribution boards and panelboards and the indicate the feeders/circuits.
Would it just be flipping breakers off and tagging? Seems very tough to accurately account time involved.
I guess there's a chance ckts may not already be identified/labeled..?Then what? Trace out circuits.
Any detail would help thanks.
 
petersonra said:
Pull the service.
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That's a good thought, then everything would be de-energized but I think the services are remaining.
But thinking along those lines and they want to keep the service switchboard but demo all load side feeders from that point on it's just matter of turning those breakers off in the service switchboard and the the entire building is dead?? Guess one would still need to verify no power all all dist. board/panel locations?
 
I would not just lock or tag the breaker. I would disconnect the load side conductors of the feeder breaker. Then you would still need to verify a de-energized state for all circuits, both feeder and branch circuits in the area that is being demolished...it is not uncommon to have a branch circuit from a feeder in another area mixed in with branch circuits from the feeder you have disconnected.

If they are doing the whole building at one time, then you just disconnect all of the feeder conductors at their source.
 
horsegoer said:
Hello All

Have a 20 story building that is being demo'ed inside.
They want electrician to tag/safe-off/disconnect power. I would qualify we are not disconnecting but tagging and safe-off.

What would involved/process for the electricians to accomplish this?
They give us existing riser and there are bunch of distribution boards and panelboards and the indicate the feeders/circuits.
Would it just be flipping breakers off and tagging? Seems very tough to accurately account time involved.
I guess there's a chance ckts may not already be identified/labeled..?Then what? Trace out circuits.
Any detail would help thanks.
Click to expand...
Honestly with what your about to attempt, can't get my mind around sending bunch "yahoos" into 20 story high-rise, armed w/bandsaws & "like equipment" w/a "rip-fest" attitude & performing this operation safely.

Also finding it hard imagine, stepping into structure & opening the main switch directly @ first, @ day-one.
I'd be looking at this, something along lines, commission of building structure, but in something of reverse.

*I'd consider having several, trained safety individuals set-up "though-out" this building w/a central command center.

*I'd have mini safety satellite centers on each floor w/ lotto red boxes with "sign-in, sign-out" clip-boards for the recording.

*Instead of one level of lotto protection, I'd consider the possibilities of employing 2 level(s) of lotto operation for safety protection.
 
don_resqcapt19 said:
I would not just lock or tag the breaker. I would disconnect the load side conductors of the feeder breaker. Then you would still need to verify a de-energized state for all circuits, both feeder and branch circuits in the area that is being demolished...it is not uncommon to have a branch circuit from a feeder in another area mixed in with branch circuits from the feeder you have disconnected.

If they are doing the whole building at one time, then you just disconnect all of the feeder conductors at their source.
Click to expand...
if the breaker is locked out and verification is made that the downstream conductors are dead, what is the point of disconnecting the load conductors?
 
petersonra said:
if the breaker is locked out and verification is made that the downstream conductors are dead, what is the point of disconnecting the load conductors?
Click to expand...
I am not going to hang my lock,my name, and company name on that for others to work on the circuits. If I am doing the work, they will be physically disconnected.
 
don_resqcapt19 said:
I would not just lock or tag the breaker. I would disconnect the load side conductors of the feeder breaker. Then you would still need to verify a de-energized state for all circuits, both feeder and branch circuits in the area that is being demolished...it is not uncommon to have a branch circuit from a feeder in another area mixed in with branch circuits from the feeder you have disconnected.

If they are doing the whole building at one time, then you just disconnect all of the feeder conductors at their source.
Click to expand...

So let's take the attached as an example. (3) feeder risers( attached) feeding 400a switch->xfrmr->dist panel-> panelboards.
Disconnecting the feeder riser at the source would de-energize the 400a switch->xfrmr->dist panel-> panelboards.
Based on what your saying you would still disconnect feeder from xfrmr to dist panel?
 

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horsegoer said:
So let's take the attached as an example. (3) feeder risers( attached) feeding 400a switch->xfrmr->dist panel-> panelboards.
Disconnecting the feeder riser at the source would de-energize the 400a switch->xfrmr->dist panel-> panelboards.
Based on what your saying you would still disconnect feeder from xfrmr to dist panel?
Click to expand...
No, only at the upstream source.
 
I guess I think it could somewhat depend on what scope of demolition is. Possible you maybe can leave feeders energized or certain feeders anyway and use them as temp power supply. Might mean disconnect all branch circuits and install some temporary branch circuits, somehow identified as something still in use for construction purposes.

Or you may disconnect all existing feeders but install some temporary wiring from the MDP for construction.

Or possibly disconnect everything for demolition and either install separate temporary service for construction or come back after demolition and make up temporary wiring and hope they demolition crew didn't destroy MDP or similar if it was to be reused.

If you are to be replacing everything then I say disconnect everything unless somehow you are using part of existing as a temp service before it gets removed.
 
I don't see the complication here. The OP post said tag, safe off, disconnect. Once disconnected, then the tags can be removed. Otherwise, it is an OSHA requirement that the people working on the wiring hang their own tag. Simple. Regarding cost, that is what an estimate is. Figure out how many circuits need to be turned off, and disconnected and how much investigation time is required to verify and viola. Either that or wild ass guess, tell them you need to charge time and material, or tell them no and maybe they will hire me to do it.
 
Strathead.. I'm in agreement.
This can be done safely, w/the right coordination and safety plan.

* Came back to add..
My "better-half" who happens to be @ home w/me today, She's Safety Rep. w/ degree & several certifications (electrical background related). This is what she does.. She's @ home working on a safety program right now, while I'm typing this. But she will not get involved, or offer any interjection, via the web.

Have a safe day..;)
 
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Strathead said:
I don't see the complication here. The OP post said tag, safe off, disconnect. Once disconnected, then the tags can be removed. Otherwise, it is an OSHA requirement that the people working on the wiring hang their own tag. Simple. Regarding cost, that is what an estimate is. Figure out how many circuits need to be turned off, and disconnected and how much investigation time is required to verify and viola. Either that or wild ass guess, tell them you need to charge time and material, or tell them no and maybe they will hire me to do it.
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You have good point in there that if asked to lock or tag it off that anyone working on it needs their own lock or tag on it per commonly followed LOTO rules.

If you disconnect/cap so that it can't be energized without reconnecting, there is very little potential for energy in the equipment being worked on without someone intentionally trying to get it energized again.
 
James L said:
No, he did not say that. He made a specific point to say they would not be disconnecting it
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Not sure if he meant not disconnecting say feeder conductors from a MDP or if he meant there will be no disconnection of service from the utility provider.
 
IMHO, the scope of the interior demo MUST be detailed to the electrical contractor. From past experience the 'demo' may be floor slab to ceiling decking, and exterior wall to wall, perhaps leaving a 'core' section intact. This scenario would result in everything except the riser(s) perhaps.
Dependent on the routing of the risers, they may also be out.

A few I was involved in, we just disconnected the load side at the main service; installed a temp panel, and GFI receptacles.
 
James L said:
No, he did not say that. He made a specific point to say they would not be disconnecting it
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He actually said those exact words in that order, followed by saying they wouldn't be disconnecting it. Since logic says that the circuits that need to be demo'd WILL need to be disconnected, I would disconnect them period to safe them off. Generally, I prefer to disconnect wires in a construction situation for the long term rather than rely on a tag out
 
I’ve been on projects where another contractor was paid to do the demo, but didn’t do a good job of it. Rooms that were supposed to be dead, were not. They just turned off the breakers, then the GC would turn them back on because he didn’t have power somewhere. No lockout/tagout.
I prefer to take it back to the hr box and disconnect it. No need for LOTO when I leave the job.
 
Strathead said:
He actually said those exact words in that order, followed by saying they wouldn't be disconnecting it. Since logic says that the circuits that need to be demo'd WILL need to be disconnected, I would disconnect them period to safe them off. Generally, I prefer to disconnect wires in a construction situation for the long term rather than rely on a tag out
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If you go back and read, you'll see where he wrote "they" (customer, gc...?) want disconnect, but he's not going to provide disconnect - only safe/off and tagged.
horsegoer said:
They want electrician to tag/safe-off/disconnect power. I would qualify we are not disconnecting but tagging and safe-off.
Click to expand...

That's why I said in post #5 there's no true safe off unless it's disconnected.
 
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