New hotel in Mc What would you do?

[Fulthrotl]

As too:
"Fulthrotl
it's a smart plug that ties with an occupancy sensor on the ceiling, and a door trip."
Sounds good could be a great upsell
would you have a name of that set up? what kind of cost & time line to install?
could that unit be controlled via remote?

my wholesale house is closed till wednesday, i'll see if i can get you something then.

install time? you are putting a plug in for the AC. it's like a GFCI in form factor,
and speed of install.

the door switch and occupancy sensor are paired with the device, and are peel and
sticks, so to speak.

put 20 minutes labor on per room, and call it good.

 

[kwired]

Yeah, they avoid bundling issues, but stacking is also part of the derating conditions. IMO, this does not alleviate a stacking condition. What say ye all?

Looks like the one in the photo will "stack" up to 4 cables, with a space between a second "stack" of up to 4 cables.

Derating is an issue that must be considered, but if you only have 2 current carrying conductors per cable, you will be less than 9 current carrying conductors in each effective "bundle" and unless ambient temperature requires additional adjustment, your selected conductor will still be same size as if there were no stacking or bundling. Get enough conductors bundled or stacked that you get into the 50% deration value and you will be increasing conductor sizes pretty much every time.

 

[Smart $]

Looks like the one in the photo will "stack" up to 4 cables, with a space between a second "stack" of up to 4 cables.

Click on the Erico link and look at the upper right diagram. No spacing.

Derating is an issue that must be considered, but if you only have 2 current carrying conductors per cable, you will be less than 9 current carrying conductors in each effective "bundle" and unless ambient temperature requires additional adjustment, your selected conductor will still be same size as if there were no stacking or bundling. Get enough conductors bundled or stacked that you get into the 50% deration value and you will be increasing conductor sizes pretty much every time.

It's not just a derating issue. The number of cables presents just as much of an issue. Assuming 208/120, 2ccc's per cable, 6 cables per room, he'd be looking at 600 cables going into the panel room!!!

 

[kwired]

Click on the Erico link and look at the upper right diagram. No spacing.


It's not just a derating issue. The number of cables presents just as much of an issue. Assuming 208/120, 2ccc's per cable, 6 cables per room, he'd be looking at 600 cables going into the panel room!!!

So he needs to derate all of these and tell the owners just how much more it will cost as compared to doing it his way and see where it goes from there.

More than 41 conductors gives you an adjustment factor of 35%. So that should mean 6 AWG for 20 amp circuits - feeders and additional panels may look cheap compared to all the home runs of 6 AWG.

I find it a little hard to believe there isn't an engineer behind the design and such issues are not resolved in the design before it even gets to the contractor. 33 rooms on a floor and they can't afford floor space for at least one mechanical room on each floor, or one in each wing or other divisions of the building? Not to mention there is likely a need for such spaces for plumbing, HVAC, fire alarm, sprinkler and associated equipment, etc.

 

[Smart $]

So he needs to derate all of these and tell the owners just how much more it will cost as compared to doing it his way and see where it goes from there.

More than 41 conductors gives you an adjustment factor of 35%. So that should mean 6 AWG for 20 amp circuits - feeders and additional panels may look cheap compared to all the home runs of 6 AWG.

Don't forget that MC cables have some non-standard derating requirements. See 310.15(B)(3)(a)(4) & (5)

I find it a little hard to believe ...they can't afford floor space for at least one mechanical room on each floor...

I believe he did say they have stacked mechanical rooms...

 

[kwired]

Don't forget that MC cables have some non-standard derating requirements. See 310.15(B)(3)(a)(4) & (5)

I was looking at that before, I was somehow hung up on their mentioning of 20 CCC's as meaning 20 in one cable, but I think they just mean 20 in one bundle of cables the more I look at it. If more than that then deration is 60% but no limit to number of CCC's over 20 and 60% still applies.


I believe he did say they have stacked mechanical rooms...

That helps - if he can put sub panels in them, I was under impression he had to make home runs for entire facility to one room that may not even be centralized on the first floor.

 

[Smart $]

That helps - if he can put sub panels in them, I was under impression he had to make home runs for entire facility to one room that may not even be centralized on the first floor.

That's a majority of the problem... only one panel room. I don't believe he has stated anything about it being centralized or not.

 

[Smart $]

I was looking at that before, I was somehow hung up on their mentioning of 20 CCC's as meaning 20 in one cable, but I think they just mean 20 in one bundle of cables the more I look at it. If more than that then deration is 60% but no limit to number of CCC's over 20 and 60% still applies.

I missed this in my previous reply because you had it in your quote of my post...

Yes, 20ccc's is per bundle, stack, etc., not just in one cable. And while these two derating requirements would cover the majority of installations, there exists the possibility where standard derating would apply when the specified conditions are not met.

 

[Fulthrotl]

Click on the Erico link and look at the upper right diagram. No spacing.


It's not just a derating issue. The number of cables presents just as much of an issue. Assuming 208/120, 2ccc's per cable, 6 cables per room, he'd be looking at 600 cables going into the panel room!!!

my experience with situations like this, is i have had customers want me to
jump thru my ash over and over, trying this solution and that one, requiring
recalculation endlessly.

in 35 years at this i've not had one of them every bear fruit. not one.

if i were where the OP is, and i'm glad i'm not, i would communicate that
i will be happy to field engineer this at my standard hourly rate, and i'd bill
it just the way an attorney does, in .1 hour increments. this includes all time
spent phoning, talking, thinking, emailing, etc.

and working with a PE towards a wet ink signed set of drawings. when this
whole thing goes sideways, i'd want a engineer of record to deal with the
AHJ.

i'd explain that rough costs of the project would be $xxx,xxx.00, and that
doing it hard and stupid, as they are bent on doing, would be approximately
400% more expensive, at a minimum. i'd put it nicer than that, but that is
what it amounts to.

and then i'd go find a real customer, instead of wasting my time with an idiot.

some of the worst offenders in this realm are property management people
in this economy. a lot of them are out of work real estate agents, trying to
survive, and their skill set does not include logic and rationale. they will talk
interminably about this, that, and the other idea, pulling the ideas out of
a dark place faster than you can write them down, and discarding them
just as quickly.

they are salespeople, and bla bla bla is their stock in trade. not logical solutions.

 

[KVA]

I don't have much input on this subject because I am a residential guy. I've seen an old hotel wired with one large feeder that wrapped around the property in the attic. They tapped off of it at each room down to a 30 amp sub panel in each room. This was done in the 50s not even sure if it's safe or legal these days. But the idea of one large feeder instead of hundreds of branch circuits from one location doesn't seem cost or effective material wise or labor wise in my opinion. But like i said I'm a resi guy.

 

[kwired]

I don't have much input on this subject because I am a residential guy. I've seen an old hotel wired with one large feeder that wrapped around the property in the attic. They tapped off of it at each room down to a 30 amp sub panel in each room. This was done in the 50s not even sure if it's safe or legal these days. But the idea of one large feeder instead of hundreds of branch circuits from one location doesn't seem cost or effective material wise or labor wise in my opinion. But like i said I'm a resi guy.

It is legal. Some industrial places do just that. Maybe even with busway so it is easier to make taps.

To help save on conductor costs, it may be a good idea to install occasional overcurrent devices and reduce feeder sizes as the load decreases along the feeder route.

Sometimes you may find a feeder that goes from floor to floor with a panel on each floor. Obviously if you started out with a 600 amp feeder by the time you get to the last floor you likley no longer have 600 amps of load to feed, so maybe putting a breaker on select floors to be able to reduce the feeder size is at least worth consideration.

 

[Fulthrotl]

It is legal. Some industrial places do just that. Maybe even with busway so it is easier to make taps.

love the optimism..... but if they aren't going for a panel closet, suggesting bus duct and plugs
is gonna be pushing a rope uphill....

"um, yesssir, those access panels in the hallway ceiling.....? well, you didn't like my
consultants idea for hinged murals over the panels in the hallway, so we are running
1,200 amp bus duct above the ceiling....."

(notice how i took my earlier post, and elevated myself to "consultant"?
i'm positioning him for the fee.... hold him still... i don't want him to twitch
when he gets the bill....)

 

[kwired]

I didn't necessarily intend to mean that busway would be good idea for the hotel in the OP. Just was answering the question of running a feeder everywhere and making taps to it for particular loads. It is legal and can have some advantages in some cases. The disadvantages are large feeder conductors in areas where there may not be much load. Reducing the ampacity of the feeder with strategically placed overcurrent devices could be another item to throw into the mix and have good results.

If the hotel in question had stacked mechanical rooms, one very well could possibly run a single feeder and tap at each floor or use panelboards with feed thru lugs and you basically have a similar install. One potential major disadvantage - if the feeder goes down all floors are down.