Barracks

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mikehughes8

Senior Member
Location
NC
This may seem a silly question but do barracks qualify as a multi-family dwelling? If so can I use 220.82 to calculate my feeder and service load? If not what would they be catagorized as??
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
I am inclined to guess that it is a single family dwelling unit, per the NEC definitions. But to clarify the situation, can you describe the barracks you are talking about? Does it have a kitchen? Does it have one or more bathrooms? Are the sleeping accomodations for one or more persons separarted from those of another group of one or more persons, and does each separate space have its own kitchen?
 

mikehughes8

Senior Member
Location
NC
Well I am here in Afghanistan trying to figure out what size generator(s) these barracks will need. Eventually the generators will be replaced by XFMRs. The barracks are nothong more than built out storage containers (8' x 20'). Each storage container is divided into 2 rooms. There are 480 of these 2-room containers. There are 40 containers in a complex for a total of 12 complexes.

Each room contains:
HVAC 10.8 RLA 1p
1100VA Fridge
Lighting load
No cooking provisions

Restrooms are including in each complex but are seperate containers within the complex. They are basically shared restrooms /showers. 2 per 40 container complex.

They contain:
2 water heaters 5000VA ea. (I haven't seen the nameplate rating)
HVAC 10.8 RLA 1p
Lights

I think that cover it. i am just trying to determine what demand factors to use
and whether or not I can use 220.82

THANKS
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
220.82 is not a player. You do not have a "dwelling unit," per the NEC definition of that phrase.

I don't think the NEC gives you any other choices than to count up everything and plan for it all to be running at the same time. If the local rules tell you that you must apply the NEC rigorously, then I think you are going to have to use a demand factor of 100%. If the local rules say to follow the NEC as closely as practical, then you are going to have to use your best judgment. The HVAC systems are likely to be running full blast, but perhaps the water heaters will not be on a much.
 

mikehughes8

Senior Member
Location
NC
I was afraid of that. I am going to need some large generators. I guess we will have to wet stack the heck out of them at night when everyone is asleep and nothing but those fridges are running. I ahte generators...transformers don't care.
 

e57

Senior Member
Having done simular things in Somalia - plan for the worst....

That said - the NEC does not apply to this field condition IMO, and even attempting to apply resi calc factors would be short selling the fact that you are not dealing with normal people in normal conditions.

One can assume this - that after any formation - there will be shifts of several hundred taking a shower, then cranking the heat, as well as the space heaters sent from home, and that electric blanket granny sent, there will also be two to three TV's and boom boxes and every single light on. Since there is a fridge (all will open simutainiously) - figure there are microwaves being shared in each.... Then there will be the next rotation for chow and showers etc is 45 minutes later. This will last from 16:00~22:00!

So I say shoot for 100% and factor 125%.... Once you have that - periodically amp out the feeders at say 18:00 (6PM) - size your eventual transformers for 125% of that.

While the generators are running.... parallel several early, then back one or two off-line so the ones that are left are pulling 80%. You'll be surprised at what comes out of a generator that has been wet-stacking all day - in just an hour or two at 80%+ while 500 jarheads are doing their best to max it.... (If you want it busted over-night - USMC) If your stuck with some navy unit, or AF units one can assume less abuse in the fact that they are not trying to tap into the electrical for bizzare entertainment reasons (As Marines would) - but they have more creature comforts for some reason - I assume they are closer to their mothers and whine for more stuff...

Since I assume you do not have a load bank - use your load as one. And if you feel comfortable with it - you can load bank them against each other by paralleling them and backing of either the throttle or voltage regulator slightly.

Yes, I was an 1142.
 
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