# Feeder size for unknown load.



## kb1jb1 (Nov 11, 2017)

How are some of you sizing feeders for empty stores? I am pricing out replacing 6 feeders from the service equipment room to six separate stores. The feeders are old and water is leaking out of them in the only basement in the complex. The original installation was done over 45 years ago and it is EMT under the concrete slabs I have no idea what size feeders were used but it looks like 1/0 copper TW on a 200 amp fused switch. There are 12 stores and the first 6 are occupied. Unit 6 has the basement where the water is dripping out of the feeders to store # 7 - #12 so feeders 7 - 12 have to be replaced. 
This is the question: The feeders are between 200 and 275 feet from the electric room to the empty stores. The stores are for rent. I have no idea of the load other than a 5 ton RTU. I am planning on jumping on the roof because the owner does not want to dig up the parking lot. We all know about the cost of materials and right now rigid aluminum conduit is the cheapest to use. The feeders could be 4/0 Aluminum or 250 kcmls, or 300 kcmls. Any thoughts. Base on 100 amp load, 125 amp load, 150 amp? Load calculations show a 100 amp is all that is needed but experience tells me otherwise. Copper conductors are more than $30,000.00 additional.


----------



## backstay (Feb 3, 2011)

I think 3/0, 4/0, and 250 are the correct sizes.

1-1/2 “ , 2 “, and 2 “


----------



## micromind (Aug 11, 2007)

backstay said:


> I think 3/0, 4/0, and 250 are the correct sizes.


Nah......too small. I usually use 4 parallel 2000 MCM CU. No chance of an overload then!!

Seriously, is it single phase or 3Ø? and if it is 3Ø, is it all 4 wires or 2 legs of a Y?

Depending on the size, a lot of places that I've seen are 100 amp 120/208 3Ø. That's nearly 30KVA, unless the shops have something exotic, they'll never be close to that amount. 

If they're good-sized shops, I'd go to 200 amps each. It'd need to be a fairly large shop to need that much. 150 amps would be quite a bit too.


----------



## backstay (Feb 3, 2011)

We’re back to dribbling out information. Single phase/3 phase. Voltage 120/240 or 120/208.


----------



## LGLS (Nov 10, 2007)

kb1jb1 said:


> How are some of you sizing feeders for empty stores? I am pricing out replacing 6 feeders from the service equipment room to six separate stores. The feeders are old and water is leaking out of them in the only basement in the complex. The original installation was done over 45 years ago and it is EMT under the concrete slabs I have no idea what size feeders were used but it looks like 1/0 copper TW on a 200 amp fused switch. There are 12 stores and the first 6 are occupied. Unit 6 has the basement where the water is dripping out of the feeders to store # 7 - #12 so feeders 7 - 12 have to be replaced.
> This is the question: The feeders are between 200 and 275 feet from the electric room to the empty stores. The stores are for rent. I have no idea of the load other than a 5 ton RTU. I am planning on jumping on the roof because the owner does not want to dig up the parking lot. We all know about the cost of materials and right now rigid aluminum conduit is the cheapest to use. The feeders could be 4/0 Aluminum or 250 kcmls, or 300 kcmls. Any thoughts. Base on 100 amp load, 125 amp load, 150 amp? Load calculations show a 100 amp is all that is needed but experience tells me otherwise. Copper conductors are more than $30,000.00 additional.


Just worry about sizing the feeder based on how much heat or air conditioning that store space is going to need. Then I had a few amps for lighting seeing is just about any new store that moves into a new space or a vacant space is going to have LED lighting and the load is going to be extremely minimal even their sign is going to be LED.

So AC and heat are the only things you have to worry about. If a store should move in such as a delicatessen or a restaurant that really has high energy needs, don’t worry about it. That’s when they call you back up and say they need an increase in their service size. Every single shopping center I know does not accommodate any store for it to use as a high energy using restaurant delicatessen pizzeria, laundromat, etc. business owners who open such doors know darn well wherever they move they’re going to have to increase their electric capacity and specifically look for places where they can do that.


----------



## SWDweller (Dec 9, 2020)

Your just replacing the wire and not the breaker panels?
The age of TW would lead me to think it would be time for new panels as well as feeders.
I have not used TW in decades. I am a big fan of XHHW.

Either way how big is the over current protection and the panels for each units? Single phase? Voltage? Local requirements?


----------



## kb1jb1 (Nov 11, 2017)

micromind said:


> Nah......too small. I usually use 4 parallel 2000 MCM CU. No chance of an overload then!!
> 
> Seriously, is it single phase or 3Ø? and if it is 3Ø, is it all 4 wires or 2 legs of a Y?
> 
> ...


Three phase. I am concerned about voltage drop. There are no perspective tenants yet. It could be a card shop with no load or a pizza place with electric ovens. I was wondering what other electricians would figure. For a 200 amp feeder I would have to use 350 AL in 3 inch conduit. $$$. I think I will let it fall back on the building owner to tell me what to do. He will probably say 60 amps.


----------



## SWDweller (Dec 9, 2020)

All you can do is fill the conduit with wire and replace the breaker feeding it and maybe the panel. After that it is crap shoot.


----------



## kb1jb1 (Nov 11, 2017)

SWDweller said:


> Your just replacing the wire and not the breaker panels?
> The age of TW would lead me to think it would be time for new panels as well as feeders.
> I have not used TW in decades. I am a big fan of XHHW.
> 
> Either way how big is the over current protection and the panels for each units? Single phase? Voltage? Local requirements?


The panels in four of the stores were changed recently. The other two I could not get into the stores. Three phase on 200 amp fuses. The fused switches are existing and they put 200 amp fuses on what looks to be 1/0 copper. Very common for shopping center strip stores. I have to check out XHHW. I was planning on that Simpull by Southwire with the super slip jacket


----------



## kb1jb1 (Nov 11, 2017)

LGLS said:


> Just worry about sizing the feeder based on how much heat or air conditioning that store space is going to need. Then I had a few amps for lighting seeing is just about any new store that moves into a new space or a vacant space is going to have LED lighting and the load is going to be extremely minimal even their sign is going to be LED.
> 
> So AC and heat are the only things you have to worry about. If a store should move in such as a delicatessen or a restaurant that really has high energy needs, don’t worry about it. That’s when they call you back up and say they need an increase in their service size. Every single shopping center I know does not accommodate any store for it to use as a high energy using restaurant delicatessen pizzeria, laundromat, etc. business owners who open such doors know darn well wherever they move they’re going to have to increase their electric capacity and specifically look for places where they can do that.


That is the way I was looking at it. I should not over think it and use 4/0 AL in 2 ' conduit. After all what is existing and has to be replaced is 1/0 copper. 250 foot runs.


----------



## SWDweller (Dec 9, 2020)

As long as you have a good sharp knife or razor blade XHHW is not difficult. 
Or you could get lazy if you have a Speed Systems kit. I have always gotten a kick out of how they size their strippers. Min size 1/2" Max size 2" pretty much includes it all. 
I have a complete kit on of the very few tools I have never loaned out. 





Speed Systems 1700SS 1/2 to 2 Wire Stripper


Wire Stripper; Type Adjustable; Wire Type High Voltage Cable; Minimum Wire Size 1/2 Inch; Maximum Wire Size 2 Inch




www.mecampbell.com





I did a lot of medium voltage splicing and terminating in the past. Felt it worth it to me to be perfect.


----------



## LGLS (Nov 10, 2007)

kb1jb1 said:


> That is the way I was looking at it. I should not over think it and use 4/0 AL in 2 ' conduit. After all what is existing and has to be replaced is 1/0 copper. 250 foot runs.


You don’t think you can utilize the underground runs that are existing? That’s a darn shame. Have you considered a sock cut straight through the floors of each and every store going one end to the other? You could even if the stores are vacant use an outdoor asphalt saw cut or concrete saw cut.


----------



## kb1jb1 (Nov 11, 2017)

LGLS said:


> You don’t think you can utilize the underground runs that are existing? That’s a darn shame. Have you considered a sock cut straight through the floors of each and every store going one end to the other? You could even if the stores are vacant use an outdoor asphalt saw cut or concrete saw cut.


Since the EMT is full of water in the exposed basement and rusted through in places,, we feel the EMT is rotted out under the slab. They just renovated some of the stores with new floors. The last store to be renovated if the lease is renewed, 
is a laundromat with a rotted out steel waste water box in the floor. This is where we think the water is coming from because the water leaking from the EMT smells like sewer water. 
I am leaning on passing on this job. Even though the customer has money, I feel there are to many questions and little engineering.


----------



## Veteran Sparky (Apr 21, 2021)

Have a engineer design it. That is how it's supposed to work. If owner won't pay for it, make sure you are clear of any and all liability. We are electricians, not 'designers'. Could we design it? Most the time...absolutely. However it is not our job.


----------



## kb1jb1 (Nov 11, 2017)

Veteran Sparky said:


> Have a engineer design it. That is how it's supposed to work. If owner won't pay for it, make sure you are clear of any and all liability. We are electricians, not 'designers'. Could we design it? Most the time...absolutely. However it is not our job.


Some of the major trade journals are encouraging design / build installations but I am finding that could be more problems than what it is worth.


----------



## Veteran Sparky (Apr 21, 2021)

kb1jb1 said:


> Some of the major trade journals are encouraging design / build installations but I am finding that could be more problems than what it is worth.


I know. It has been pushed forever. People do not want to pay Arch/Eng fees, when they can intimidate electricians to do it because Sparky is afraid to lose the job. It is absolute bullshit. Except for rural, most cities need stamped engineer drawings to pull permit. Are you an engineer? Judge doesn't care if you're capable of design if you do not have eng degree.
Sticks in my crawl. Architects are not allowed to design electrical. However you see it all the time. Problem is there is no consistent enforcement in this country. Municipalities/cities are understaffed, everything is outsourced to third party, and neither will be held accountable. Ever try to fight a municipality and code enforcement party because they screwed up? I have...it is a lose lose situation.
Code inspectors are inept, do not fully understand the code, and there is too much he said she said when it comes to the code. Whole other topic. I digress


----------



## Almost Retired (Sep 14, 2021)

very sad and very true


----------



## Southeast Power (Jan 18, 2009)

SWDweller said:


> Your just replacing the wire and not the breaker panels?
> The age of TW would lead me to think it would be time for new panels as well as feeders.
> I have not used TW in decades. I am a big fan of XHHW.
> 
> Either way how big is the over current protection and the panels for each units? Single phase? Voltage? Local requirements?


I agree on the XHHW, the next generation of electricians are going to laugh all the way to the bank pulling out all of the THHN/ THWN we have been installing underground.


----------



## Southeast Power (Jan 18, 2009)

kb1jb1 said:


> Some of the major trade journals are encouraging design / build installations but I am finding that could be more problems than what it is worth.


I Have done millions of design-build projects. I prefer to do the design and if it's too large for me to legally sign, I spoon-feed an engineer. Im so sick and tired of plans that do work and trying to fit pieces and parts where they don't belong.


----------



## Veteran Sparky (Apr 21, 2021)

kb1jb1 said:


> How are some of you sizing feeders for empty stores? I am pricing out replacing 6 feeders from the service equipment room to six separate stores. The feeders are old and water is leaking out of them in the only basement in the complex. The original installation was done over 45 years ago and it is EMT under the concrete slabs I have no idea what size feeders were used but it looks like 1/0 copper TW on a 200 amp fused switch. There are 12 stores and the first 6 are occupied. Unit 6 has the basement where the water is dripping out of the feeders to store # 7 - #12 so feeders 7 - 12 have to be replaced.
> This is the question: The feeders are between 200 and 275 feet from the electric room to the empty stores. The stores are for rent. I have no idea of the load other than a 5 ton RTU. I am planning on jumping on the roof because the owner does not want to dig up the parking lot. We all know about the cost of materials and right now rigid aluminum conduit is the cheapest to use. The feeders could be 4/0 Aluminum or 250 kcmls, or 300 kcmls. Any thoughts. Base on 100 amp load, 125 amp load, 150 amp? Load calculations show a 100 amp is all that is needed but experience tells me otherwise. Copper conductors are more than $30,000.00 additional.


Where are the engineered drawings? why would you accept liability for this?


----------



## kb1jb1 (Nov 11, 2017)

Veteran Sparky said:


> Where are the engineered drawings? why would you accept liability for this?


NY does not require engineered drawings. If I have to supply drawings, then I will be $5,000.00 or more higher in price. It's a feeder and panel with an unknown load to a 2,000 sq-ft unit. I have no problem with doing a load calculation and going from there. The existing that has to be replaced is 2/0 copper THW on a 200 amp breaker @ 285 -300 feet +/-.


----------



## Veteran Sparky (Apr 21, 2021)

kb1jb1 said:


> NY does not require engineered drawings. If I have to supply drawings, then I will be $5,000.00 or more higher in price. It's a feeder and panel with an unknown load to a 2,000 sq-ft unit. I have no problem with doing a load calculation and going from there. The existing that has to be replaced is 2/0 copper THW on a 200 amp breaker @ 285 -300 feet +/-.


I was going off #1 post which is a little more complex than changing feeders for 'a panel'. I have been doing this for a LOOOONG time and I know longer let owners, developers, architects, GC's try and intimidate or passive aggressively impress on me to do what they want because they don't want to spend the money to have it designed. $5000 is light too btw. If they take short cuts I walk. I have enough 'proper' work to do.


----------



## Veteran Sparky (Apr 21, 2021)

kb1jb1 said:


> NY does not require engineered drawings. If I have to supply drawings, then I will be $5,000.00 or more higher in price. It's a feeder and panel with an unknown load to a 2,000 sq-ft unit. I have no problem with doing a load calculation and going from there. The existing that has to be replaced is 2/0 copper THW on a 200 amp breaker @ 285 -300 feet +/-.


Unknown load...doesnt matter. If your feeding a 200a panel board, you need to size the feeder for that.
Pushing 300' you are looking at 400kcmil cu if you want to stay with in 3% VD. If these are future stores with mystery loads, you have nothing to go off of. Your customer is telling you 200a in a store, than it needs to be 200a. I would tell him it needs to be designed. If you're telling me municipality doesn't required drawings for this, I would still tell owner it needs to be designed. You should always have an elec engineer in your tool belt for these circumstances. Take eng price and add 5%.


----------



## kb1jb1 (Nov 11, 2017)

Veteran Sparky said:


> Unknown load...doesnt matter. If your feeding a 200a panel board, you need to size the feeder for that.
> Pushing 300' you are looking at 400kcmil cu if you want to stay with in 3% VD. If these are future stores with mystery loads, you have nothing to go off of. Your customer is telling you 200a in a store, than it needs to be 200a. I would tell him it needs to be designed. If you're telling me municipality doesn't required drawings for this, I would still tell owner it needs to be designed. You should always have an elec engineer in your tool belt for these circumstances. Take eng price and add 5%.


Several reasons I am losing jobs. 1. Told to bid on replacing exactly what is there which is 2/0 THW. 2. Follow the prints but we need an electrical inspection certificate. The prints are wrong so it won't pass the inspection. Now everybody is caught in a passing contest. For these two reasons I figured the job the way it should be and added 40%. A way of saying I don't want the job without saying it.


----------



## Djea3 (Mar 8, 2019)

kb1jb1 said:


> NY does not require engineered drawings. If I have to supply drawings, then I will be $5,000.00 or more higher in price. It's a feeder and panel with an unknown load to a 2,000 sq-ft unit. I have no problem with doing a load calculation and going from there. The existing that has to be replaced is 2/0 copper THW on a 200 amp breaker @ 285 -300 feet +/-.


IN 2002 I purchased a commercial building in Clearwater, FL. Decided to put in 4 ADA BATHROOMS. Took the design from the federal register of ADA approved designs. It had a FEDERAL STAMP good in ALL jurisdictions in the USA.

Clearwater REQUIRED a wet stamp. The ONLY change was a note for the plumber to connect to existing septic lines to code. That cost me over $2000 for the stamp in 2003!!! That was for an exact copy of the federally approved design!

If you are only charging $5000 today to do actual WORK in design then you are leaving money on the table and taking liability. No one will design anything for under 200 an hour. That is 25 hours work at 5000.. If they BID the design then it is a LOT higher. My guess is that to design and list all codes, parts, connection types, pull box locations etc, as well as create all necessary drawings and details will take a LOT more than 25 hours. Many EC's are charging over 120 per man hour in major cities for workers doing this kind of work (meaning you are not upgrading to LED lighting or adding a circuit, or making a new drop for powering of equipment). Design is a lot more $$.

With regard to loads, somewhere I saw codes on general service and lighting load minimums per square ft in commercial buildings. As I recall it was higher than residential 5 watts instead of 3 per ft type of difference??? ( I don't remember), plus any known loads such as HVAC and equipment. Personally, I would over-design the main panels to make it easier on the owner to rent to anyone. But that is really HIS decision. Flexibility is to the OWNER advantage and the cost difference is actually minimal relative to the return on investment.


----------



## kb1jb1 (Nov 11, 2017)

Djea3 said:


> IN 2002 I purchased a commercial building in Clearwater, FL. Decided to put in 4 ADA BATHROOMS. Took the design from the federal register of ADA approved designs. It had a FEDERAL STAMP good in ALL jurisdictions in the USA.
> 
> Clearwater REQUIRED a wet stamp. The ONLY change was a note for the plumber to connect to existing septic lines to code. That cost me over $2000 for the stamp in 2003!!! That was for an exact copy of the federally approved design!
> 
> ...


I said $5,000.00 or higher for engineering fees. I was more looking for people's experience/ opinion. Engineers don't have real life experience while electrical contractors do. I could do a load calculation which would come out to around 50 amps three phase but experience tells me to anticipate higher but how high? 100 amps? 125? 200? It has been a while since I have done strip stores and back then we only ran 100 amps, 208/120 volts, three phase. If I figure a full 200 amps then for these long runs it will be over $100.00 per foot. Times six runs. That will scare the customer away and he will just find some Hack to do the job. In many areas a component electrical contractor is allowed to design build. Many times the engineer goes to the contractor to design the job anyway. Engineers have little experience with putting their designs to work, what materials are available, or if their designs will work in the real world. Probably the main reason for an engineer is the liability insurance. If that is he case then up the insurance coverage.


----------



## Djea3 (Mar 8, 2019)

kb1jb1 said:


> 100 amps? 125? 200? It has been a while since I have done strip stores and back then we only ran 100 amps, 208/120 volts, three phase. If I figure a full 200 amps then for these long runs it will be over $100.00 per foot.


There might be other considerations, for most (depending upon the size of the units) 100 amps will be fine. However, there is a difference in conduit size to upgrade to 200 amp service. You might convince the owner to upgrade conduit for 200 amps ( at least on the most likely units to later need it) and provide 100 or 125 . Conduit isn't cheap but having future upgrade ability without re-run of conduit makes sense (especially when break through in roofs are involved). Labor doesn't change significantly for that equation. There is nothing wrong with quoting the differences in conduit sizes and the advantages, then maximizing the amperage value, there isn't any real difference in panel cost. Without calculating, it may be the same size wire for 100 and 125 amp because of the distance involved? I have had that sort of thing happen before, wire size just a little too small for minimum amp rating but next size up will carry higher rating?
At 200-300 ft away there is also the question of whether POCO can install a new transformer close to the units and you install a new meter bank or move the old one? if the owner wants a good upgrade, now is the time to look at that as it can cost the same (more or less) and reduce future maintenance and upgrade costs and possibly save over the roof runs. Lots of possibilities really. But I feel for you when the customer has no idea what they want or even need.


----------



## LGLS (Nov 10, 2007)

Veteran Sparky said:


> Unknown load...doesnt matter. If your feeding a 200a panel board, you need to size the feeder for that.
> Pushing 300' you are looking at 400kcmil cu if you want to stay with in 3% VD. If these are future stores with mystery loads, you have nothing to go off of. Your customer is telling you 200a in a store, than it needs to be 200a. I would tell him it needs to be designed. If you're telling me municipality doesn't required drawings for this, I would still tell owner it needs to be designed. You should always have an elec engineer in your tool belt for these circumstances. Take eng price and add 5%.


Why?

Every shop in the Smithaven Mall has a 60a 277/480 disco and a step-down. Walt Whitman is worse with a 90a 120/208 provided for each shop. If a tenant requires more that’s completely on them to augment it, you’re under no obligation to provide for the worst case scenario. Shop owners like delis and bakeries and heavy electrical or plumbing/ventilation requirements know what they’re in for no matter where they locate.

Code requires 1 receptacle, exit signs, emergency egress lighting and ONE fixed lighting fixture for a C of O.


----------



## kb1jb1 (Nov 11, 2017)

Djea3 said:


> There might be other considerations, for most (depending upon the size of the units) 100 amps will be fine. However, there is a difference in conduit size to upgrade to 200 amp service. You might convince the owner to upgrade conduit for 200 amps ( at least on the most likely units to later need it) and provide 100 or 125 . Conduit isn't cheap but having future upgrade ability without re-run of conduit makes sense (especially when break through in roofs are involved). Labor doesn't change significantly for that equation. There is nothing wrong with quoting the differences in conduit sizes and the advantages, then maximizing the amperage value, there isn't any real difference in panel cost. Without calculating, it may be the same size wire for 100 and 125 amp because of the distance involved? I have had that sort of thing happen before, wire size just a little too small for minimum amp rating but next size up will carry higher rating?
> At 200-300 ft away there is also the question of whether POCO can install a new transformer close to the units and you install a new meter bank or move the old one? if the owner wants a good upgrade, now is the time to look at that as it can cost the same (more or less) and reduce future maintenance and upgrade costs and possibly save over the roof runs. Lots of possibilities really. But I feel for you when the customer has no idea what they want or even need.


You gave me an idea to throw out to the building owner. The stores are empty so that is why I am questioning the feeder size. No sense running 200 amps to a card shop or 100 amps to a Bagel store. The conduit runs are the hard part so I will break out the conduit runs from the whole price and propose installing empty 2 1/2 inch EMT. They can size and pull wires when they get a tenant. I gave the option of adding a utility pad transformer closer to the stores but there are too many obstructions in the ground plus they did not want to dig up the parking lot.


----------



## LGLS (Nov 10, 2007)

kb1jb1 said:


> You gave me an idea to throw out to the building owner. The stores are empty so that is why I am questioning the feeder size. No sense running 200 amps to a card shop or 100 amps to a Bagel store. The conduit runs are the hard part so I will break out the conduit runs from the whole price and propose installing empty 2 1/2 inch EMT. They can size and pull wires when they get a tenant. I gave the option of adding a utility pad transformer closer to the stores but there are too many obstructions in the ground plus they did not want to dig up the parking lot.


You still have to provide the basics in each space unless the C of O is already acquired.


----------

