Multi-Family Feed Thru's

[HoosierSparky]

I am slightly puzzled by this one-line. Wire sizes check out. That is not the problem. My concern is using panels as feed through's. Each panelboard has a MCB. There will be firestopping between floors per 300.21.

One of my other concerns is the staggering of phases through the floors. I've usually started with "if it doesn't look right, it probably isn't." This is one of those. I feel I am missing something, but I cannot put my finger on it? Suggestions?

Thanks.

 

[jaggedben]

Does the drawing show the panels used as feed throughs or does it show them each tapped off the feeder as it goes? I would say the drawing lacks detail, for example it doesn't show the MCBs you refer to.

I would send an RFI to whoever produced the drawing.

 

[peter d]

Is it individually metered? :? If so, there's no chance it's a compliant design.

 

[HoosierSparky]

Does the drawing show the panels used as feed throughs or does it show them each tapped off the feeder as it goes? I would say the drawing lacks detail, for example it doesn't show the MCBs you refer to.

I would send an RFI to whoever produced the drawing.

MCB's are called out on the panel schedules. They are also NOT individually metered. Not much other detail provided. In 80 sheets, I have maybe 6 that didn't have corrections marked up.

 

[Joe Villani]

This is a common design in NYC public housing.

Typically the back box is wider than the standard load center back box to accommodate the taps.

https://www.google.com/url?sa=t&sou...FjACegQICRAB&usg=AOvVaw1Dxd1G9V0ezvKuB-gE3gfF

 

[electrofelon]

not necessarily anything wrong. I believe they are called "riser panels". Basically its one larger feeder that uses feeder taps to each unit panel. Just make sure the taps are done per 240.21 and 408.36 is met.

 

[HoosierSparky]

Thanks all.

 

[peter d]

I learned something new today. :thumbsup:

 

[Adamjamma]

So how would you do it if you had no available riser panels but needed to daisy chain? Especially given the bending radius and the lack of through lug panels as well... seems they are no longer available unless less than 8 breakers...

just use main lug panels with back fed breaker as main main breaker and a double lug converter for the splice? Or is there an easier way? Or run two breakers... one in, one out? Again losing four spaces on the panel??

Having sourcing issues with suppliers in Caribbean right now..lol..all we seem to b3 locating is main lug panels with no more through lug capability... is there a way to add through lugs to a main lug panel?

 

[kwired]

So how would you do it if you had no available riser panels but needed to daisy chain? Especially given the bending radius and the lack of through lug panels as well... seems they are no longer available unless less than 8 breakers...

just use main lug panels with back fed breaker as main main breaker and a double lug converter for the splice? Or is there an easier way? Or run two breakers... one in, one out? Again losing four spaces on the panel??

Having sourcing issues with suppliers in Caribbean right now..lol..all we seem to b3 locating is main lug panels with no more through lug capability... is there a way to add through lugs to a main lug panel?

Difficult to come up with "loadcenters" with subfeed lugs other than mentioned 8 space units, but you have a lot more choices if you go with a commercial panelboard. My experience with Square D, both NQ and NF, is if you want subfeed lugs you order a subfeed lug kit and add whatever dimension it calls for to the cabinet you will house it in.

Adding subfeed lugs to existing NQ or NF panel - you won't have needed wire bending space if you don't also increase length of the cabinet. That said, I have some 400 amp NF panels that I could easily install the main lugs that were removed for the main breaker kit on the other end of the bus. I won't have same shields or same wire bending space I would have if actually properly installing their 400 amp subfeed lug kit, but seems to be a fair amount of room to add say a 200 amp feeder tap conductor to the subfeed lugs if I wanted. Also note that subfeed lug kit also comes with additional neutral lug intended for the sub-feeder.

 

[electrofelon]

So how would you do it if you had no available riser panels but needed to daisy chain? Especially given the bending radius and the lack of through lug panels as well... seems they are no longer available unless less than 8 breakers...

just use main lug panels with back fed breaker as main main breaker and a double lug converter for the splice? Or is there an easier way? Or run two breakers... one in, one out? Again losing four spaces on the panel??

Having sourcing issues with suppliers in Caribbean right now..lol..all we seem to b3 locating is main lug panels with no more through lug capability... is there a way to add through lugs to a main lug panel?

Difficult to come up with "loadcenters" with subfeed lugs other than mentioned 8 space units, but you have a lot more choices if you go with a commercial panelboard. My experience with Square D, both NQ and NF, is if you want subfeed lugs you order a subfeed lug kit and add whatever dimension it calls for to the cabinet you will house it in.

Adding subfeed lugs to existing NQ or NF panel - you won't have needed wire bending space if you don't also increase length of the cabinet. That said, I have some 400 amp NF panels that I could easily install the main lugs that were removed for the main breaker kit on the other end of the bus. I won't have same shields or same wire bending space I would have if actually properly installing their 400 amp subfeed lug kit, but seems to be a fair amount of room to add say a 200 amp feeder tap conductor to the subfeed lugs if I wanted. Also note that subfeed lug kit also comes with additional neutral lug intended for the sub-feeder.

One could also just have a pull box next to each loadcenter/panelboard and tap the conductors there. Would need a MB panel (or backfed as main) for tap conductor protection and 408.36.

Its a wierd set up, but I guess sometimes it works out to be cost effective. No way to meter without submetering which seems like a big negative.

 

[Adamjamma]

Difficult to come up with "loadcenters" with subfeed lugs other than mentioned 8 space units, but you have a lot more choices if you go with a commercial panelboard. My experience with Square D, both NQ and NF, is if you want subfeed lugs you order a subfeed lug kit and add whatever dimension it calls for to the cabinet you will house it in.

Adding subfeed lugs to existing NQ or NF panel - you won't have needed wire bending space if you don't also increase length of the cabinet. That said, I have some 400 amp NF panels that I could easily install the main lugs that were removed for the main breaker kit on the other end of the bus. I won't have same shields or same wire bending space I would have if actually properly installing their 400 amp subfeed lug kit, but seems to be a fair amount of room to add say a 200 amp feeder tap conductor to the subfeed lugs if I wanted. Also note that subfeed lug kit also comes with additional neutral lug intended for the sub-feeder.

thanks. Used to get through lug 20/40 and 20/30 roughly panels from someplace.. dont remember who now... but seems like we dont have as much choice in Jamaica... you are stuck with whatever the suppliers in Kingston imported... not always good things but because they are not importing them in, we dont require AFCI or GFCI so far...

 

[Adamjamma]

. No way to meter without submetering which seems like a big negative.

In Jamaica am mostly needing it for multi story single family homes... local code requires you to have a panel on each floor for that floor, in an accessible place... such as a hallway...
Kind of a take off on the British code that required it to be accessible...
So, if you have three floors plus a basement you have four panels in the house... if you have any apartments in the house they get separate panels and services unless you want to share circuits with them...

Gets kind of wild as I had to work on one home that had seven floors plus a cabana... and four apartments as well... the guy was upset because the inspectors had come in due to a complaint in one apartment, and made him add two panels he had not thought he needed... in the USA he would not need them...lol... whole home used 275 amps including the apartments... lol

 

[kwired]

One could also just have a pull box next to each loadcenter/panelboard and tap the conductors there. Would need a MB panel (or backfed as main) for tap conductor protection and 408.36.

Its a wierd set up, but I guess sometimes it works out to be cost effective. No way to meter without submetering which seems like a big negative.

If you don't need to meter, feeders that supply multiple panels may be cost effective.

I run into low income housing complexes at times where there is no individual tenant metering.

Never worked on but have seen campus housing, resorts or similar situations where there is no individual metering for each unit either.

Typical for profit apartment complex or even commercial multi-tenant typically the tenant pays their utilities separately from their rent/lease, then such feeders to multiple tenants becomes less practical.