How does an electrician wire multi-floors

[Designer69]

I have a dorm building with individual dwelling units and separate boarding type areas with individual sleeping rooms, corridors etc.

there are multiple occupied levels and a basement where the electrical equipment is stored.

The house panel is in the basement and all loads (receptacles, lights etc.) on first and second floors will have to be fed by the house panel.

Would an electrician actually do it this way and wire home runs to the upper floors from the basement house panel or is it a must he would install additional house panels on each individual floor?

Thank You

 

[Coppersmith]

It could be done either way. Usually there is a savings in time and material by putting one or more subpanels on each floor. Voltage drop (or the need to counter it) will also be lessened. There may be security reasons to keep all panels far away from the residents.

 

[LarryFine]

Agreed on all points above. A single 100a feeder can supply a lot more than 100a of individual circuits.

I prefer sub-panels but it depends on distances, number of circuits per floor, and comparative costs.

Without knowing the details, it also looks more "professional" to have a panel for each floor or area.

 

[kwired]

If it has "individual dwelling units" you are most likely to see a panel in each unit in most installations.

 

[mbrooke]

How long are the typical home runs? If we are talking less than 100 feet a panel in the basement would be fine, if more than that sub-panel would be my doing. Janitor closet for the panels if there is fear of abuse or misuse. Considering that these are dwellings I'd imagine there will be many circuits, so that alone might call for sub-panels.

 

[Designer69]

How long are the typical home runs? If we are talking less than 100 feet a panel in the basement would be fine, if more than that sub-panel would be my doing. Janitor closet for the panels if there is fear of abuse or misuse. Considering that these are dwellings I'd imagine there will be many circuits, so that alone might call for sub-panels.

Thank you. Yes you are right, many circuits. I'd say max distances could be up to 200 feet. This sounds like leaning on the side of sub-panels

 

[Dennis Alwon]

Sub panels without a doubt.. You will save on the labor and cost of materials is probably not much different

 

[mbrooke]

Thank you. Yes you are right, many circuits. I'd say max distances could be up to 200 feet. This sounds like leaning on the side of sub-panels

Welcome

200 feet I'd definitely consider sub-panels for more than a few circuits. Both for labor, cost (ie AL feeder) and above all voltage drop. One or two branch circuits could get loaded to 100%, however the odds of a properly sized feeder hitting even 70% is nil and as such VD will always be low.

 

[Dennis Alwon]

Also, who wants to run down 3 flights of stairs to reset a breaker. Adding a new circuit would be impossible with the panels in the basement.

I don't do much commercial but where I have there was always a panel on every floor that controlled all circuits on that floor.

 

[Strathead]

I have a dorm building with individual dwelling units and separate boarding type areas with individual sleeping rooms, corridors etc.

there are multiple occupied levels and a basement where the electrical equipment is stored.

The house panel is in the basement and all loads (receptacles, lights etc.) on first and second floors will have to be fed by the house panel.

Would an electrician actually do it this way and wire home runs to the upper floors from the basement house panel or is it a must he would install additional house panels on each individual floor?

Thank You View attachment 20439

I see you are a design engineer but you don't list your experience, so I apologize if this is below your level. "Dwelling units" have specific code requirements including the requirement that the resident has access to the breakers. this is why you usually see individual loadcenters in dwelling units including those efficiency units in hotels. The rest can be fed from panels behind locked doors

 

[Designer69]

I see you are a design engineer but you don't list your experience, so I apologize if this is below your level. "Dwelling units" have specific code requirements including the requirement that the resident has access to the breakers. this is why you usually see individual loadcenters in dwelling units including those efficiency units in hotels. The rest can be fed from panels behind locked doors

Nothing is below my level haha. But yes I agree, the 2 dwelling units in the building do have their own load centers. However there are good sized other common "boarding" type areas outside of the individual dwelling units that I am more curious about.

 

[Strathead]

Nothing is below my level haha. But yes I agree, the 2 dwelling units in the building do have their own load centers. However there are good sized other common "boarding" type areas outside of the individual dwelling units that I am more curious about.

I did a 5 story 102,000 square foot dorm building with a service on the first floor it fed a distribution panel on each floor and that in turn fed 5 200 amp sub panels out in closets on the wing. The top floor had an additional distribution panel to feed rooftop AC units. This entire building was a conduit and MC building.

I did an assisted living facility where every unit had a 60A 6-12 load center fed with SE cable. aluminum legal rising between floors and above acoustical ceiling and then the spaces were Romex. very economical.

 

[Designer69]

I did a 5 story 102,000 square foot dorm building with a service on the first floor it fed a distribution panel on each floor and that in turn fed 5 200 amp sub panels out in closets on the wing. The top floor had an additional distribution panel to feed rooftop AC units. This entire building was a conduit and MC building.

I did an assisted living facility where every unit had a 60A 6-12 load center fed with SE cable. aluminum legal rising between floors and above acoustical ceiling and then the spaces were Romex. very economical.

Yeah 102,000 SF is definitely understandable. This space I'm working on is about 6,000 SF per foor with about 1,500 out of the 6,000 being the dwelling unit per floor.

 

[mbrooke]

I see you are a design engineer but you don't list your experience, so I apologize if this is below your level. "Dwelling units" have specific code requirements including the requirement that the resident has access to the breakers. this is why you usually see individual loadcenters in dwelling units including those efficiency units in hotels. The rest can be fed from panels behind locked doors

I agree- but code makes provision if one site maintenance exists that can get to the load centers.

 

[kwired]

I agree- but code makes provision if one site maintenance exists that can get to the load centers.

Yes. Dormitories, hotels, resorts, assisted living centers are a few examples where you may not find a panel within an individual dwelling unit at times. Many times you still find them within the unit in such places though because it is simpler and less cost then to do it other ways.

 

[mbrooke]

Yes. Dormitories, hotels, resorts, assisted living centers are a few examples where you may not find a panel within an individual dwelling unit at times. Many times you still find them within the unit in such places though because it is simpler and less cost then to do it other ways.

Yahhh, thats true. A bit off topic but I know of old places that would take a 4/0, run it straight through the attic and split bolt off of it down to a main breaker sub-panel. Not sure if code has anything now disallowing it be its technically doable under tap rules. Still done with "riser" panels in apartments.

 

[peter d]

Yahhh, thats true. A bit off topic but I know of old places that would take a 4/0, run it straight through the attic and split bolt off of it down to a main breaker sub-panel. Not sure if code has anything now disallowing it be its technically doable under tap rules. Still done with "riser" panels in apartments.

I'm 99.99% sure that method is only permissible in industrial settings, I believe the code article is "Open wiring on insulators".

 

[mbrooke]

I'm 99.99% sure that method is only permissible in industrial settings, I believe the code article is "Open wiring on insulators".

Even if the splices are J-box enclosed?

 

[peter d]

Even if the splices are J-box enclosed?

I've never heard of or seen the method you describe. :huh: Certainly seen high rise apartment buildings with bus duct through the floor and a large fused bus plug feeding the meter packs on each floor, but never individual conductors.

 

[mbrooke]

I've never heard of or seen the method you describe. :huh: Certainly seen high rise apartment buildings with bus duct through the floor and a large fused bus plug feeding the meter packs on each floor, but never individual conductors.

Here is the riser method, conductors are encased:

http://forums.mikeholt.com/showthread.php?t=159120&p=1542199#post1542199


The method I have in mind also has the conductors enclosed, but the taps are in the attic and run down to the subpanel.