Neutral conductor of a 5-wire, 2-phase, system is it CC?

Merry Christmas
The 140% thing comes from 2 phase 3 wire. You have 2 hots and a grounded conductor, with the H-N voltage of 'phase B' 90 degrees away from 'phase A'. In this configuration if you have 10A on each hot leg, you get 14A on the neutral. In 2 phase 3 wire you most certainly count the grounded (not neutral) conductor as a CCC.
Yeah
That 141% wire could also be bonded to ground and then you could use 2 pole discos and motor starters
 
The 140% thing comes from 2 phase 3 wire. You have 2 hots and a grounded conductor, with the H-N voltage of 'phase B' 90 degrees away from 'phase A'. In this configuration if you have 10A on each hot leg, you get 14A on the neutral. In 2 phase 3 wire you most certainly count the grounded (not neutral) conductor as a CCC.

But you (OP) were talking 2 phase 5 wire, with 4 hots and a grounded conductor that _is_ a neutral. You still need the oversized neutral because you _might_ only have two phases supplying load, but in the case of all 4 hots supplying equal load the neutral current drops to zero. The total number of CCCs for derating is 1 less than the total number of wires.

Let's assume a circuit rating of 100A, and consider all of the 'fully loaded' combinations (meaning some hots have full current, others have 0):
Circuit A carries 100A -> N carries 100A, 2 conductors worth of heating
Circuits A and B each carry 100A -> N carries 140A, between 3 and 4 conductors worth of heating (because of the oversized N)
Circuits A, B, and C each carry 100A -> N carries 100A, less than 4 conductors worth of heating (again because of the oversized N)
Circuits A, B, C, and D each carry 100A -> N carries 0A, 4 conductors worth of heating.
We had a brilliant retired Navy engineer that reused 2,300 volt to 240 volts transformers to step up 240 volts to 2,300 volts two.phase three wire for a new building. Building needed two.phase 240 volts for 8 used two phase ammonia compressors.
 
I saw a lot of those. It got really hard to get 2 phase equipment later.

We even use to use the 4 wire delta high leg to get 2 phase out of sometimes. A-C (240v) was one phase and B-N (208v) was your second phase. They were 90 degrees apart but different voltages, so one phase did a bit more work. Most times it was some ancient machine tool, and the guy never worked it to capacity anyway.
I'm not sure if you remember North I Engines over on B Street, but they had a 2 phase building they used for storage and they ran it off of a 3 phase generator to power the elevator and hoists. If I remember right he just put 3 phase to the 2 phase equipment and ran it. But that was really low duty cycle. They were the local Waukesha Engine and generator dealer. Adam Talacki (RIP), AKA "The world's Smartest Pollack". And believe me, the guy was wicked smart, so he earned that name
I do not remember North American Engines but we were located at Front & Venago Streets. Down the street from the SKF bearing plant. I wired in a small store in Mayfair during a natural gas storage so they went with a three phase roof top AC unit with electric heat.Installed a 100 amp single phase & a three phase 240 volt 100 amp service. Area was still feed by two phase and they ( PECO ) only bought in four energised wires and a grounded conductor.to basement end box. One wire of course was the same aluminum gauge as the others feed one leg if the three phase & one side of the single phase. Have to.love it when utility company only use wire that we would rate for maybe 70 amps to feed 200 amps. The electric heater drew around 70 amps and the store had a lot of 8' old fluorescent four tube T12 luminars so with the heat on that 70 amp wire could be drawing over 100 amps .
 
I don't think that's right. See posts #6 and #11.

I wasn't clear in my statement. I said 'The total number of CCCs for derating is 1 less than the total number of wires.' at the end of a paragraph where I identified a _specific_ situation (2 phase, 5 wire with neutral). What I should have said was 'In this specific situation the total 'wires worth of heating' is at most 1 less than the total number of wires.'

-Jonathan
 
I do not remember North American Engines but we were located at Front & Venago Streets.
North American was right by B & Allegheny.

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He owned the building to the left in the photo also. And a big auto parts warehouse on Fairmont, not to mention an industrial park he built in Bensalem. Always in work clothes

Yeah I know all the time I see really small service drops connected to big service entrance conductors especially in Philly. They are usually short though. Not enough loss to worry about, limits AFC, cheaper, and they make own rules
 
North American was right by B & Allegheny.

View attachment 2580992

He owned the building to the left in the photo also. And a big auto parts warehouse on Fairmont, not to mention an industrial park he built in Bensalem. Always in work clothes

Yeah I know all the time I see really small service drops connected to big service entrance conductors especially in Philly. They are usually short though. Not enough loss to worry about, limits AFC, cheaper, and they make own rules
There were so many manufacturer's in Philly back in the day. When I complained to my dad how many smoke stacks I could see at night while climbing high trees at night he said that means the business was was working at least two shifts a day that provided good wages to put a roof over families heads, feed them and provide money for a car. Unfortunately when big companies close up they affect smaller businesses. When the Philadelphia Naval Yard closed up the industrial hardware supply that we used had to lay off the two salesman that the yard was their only account and a least one person in the warehouse.
 
There were so many manufacturer's in Philly back in the day. When I complained to my dad how many smoke stacks I could see at night while climbing high trees at night he said that means the business was was working at least two shifts a day that provided good wages to put a roof over families heads, feed them and provide money for a car. Unfortunately when big companies close up they affect smaller businesses. When the Philadelphia Naval Yard closed up the industrial hardware supply that we used had to lay off the two salesman that the yard was their only account and a least one person in the warehouse.
Yeah, remember Budd Company, Dodge Steel Foundry, Midvale Steel.

Do you remember McHugh Brothers Crane Rental? I did some crazy stuff with them. Durkin Contractors over on Grant is closed up. JD Morrisey, and Anderson aren't what they once were either

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Can remember the two busy Budd plants. The one on Red Lion Road made smsll.planes during WW2. Dodge steel had to be a bad place to work. They had adds in the Sunday paper for electricians at least six tines a year. A school Iowa's built on that site.Can remember the Frankford Arsenal & the Philippines Navy Yard because every summer we would go there in annual open house week and get to walk the flight deck if a WW2 air craft carrier and climb on an old tank. Phillco Ford and the two SKF buildings probably had over 2,500 workers at one time. Do remember that crane company, Dunkin & JD Morrisey. Actually helped a friend install a machine in a company called Midvale Hepestall. ( they made cannon balls for the civil war ). Stetson hats in Kensington bonds had several thousand workers. Morrisey sold off corner portion for a new Wawa a few years ago. If you drive down Linden Avenue yoh can see where they have 70 year old graders and equipment parked there last 50 years.
 
Midvale Hepestall.
Yeah, that was the place. Bob Forepaugh tore that down for Allegheny Iron. Big Damn job. Bought himself 11 acres on the Delaware in Bensalem with a 14 room 250 year old brick home. He gutted it and redid it all, plus a giant in ground pool, boat ramp, dock,,,,,,,,,,,,,,,,,, all on the profit from that job.

Poor guy didn't live to be 70 though. Crane he was operating made contact with a 7.2kv primary at a JDM concrete batch plant he was tearing down in Telford. Guys working with him were burning steel, big stuff, like liquid OX with an auxiliary vaporizer kinda big cutting. So they become aware that the crane is on fire, and Bob was laying on the ground and unresponsive. So they get down to help Bob and somebody bumps into the outrigger box. They burned for half an hour before PP&L got that circuit deenergized. It was all really bad, and 20 years later I can still see the fallout in the families. I think that was 2003 or maybe 04.
 
Just yesterday I did my re-cert class for MEWP and aerial lifts (there's four hours I won't get back), the instructor really emphasized situational awareness and understanding swing space (and clearance distances from MV/HV lines).

(Relevant to clearances- I manage a small Masonic building and we'd like to paint it but... 10' sidewalks and 12KV lines on both streets next to the building, the PoCo engineer I talked to about the voltage was stumped about how to do it legally without taking those lines out of service, which would Not Be Cheap.)
 
Just yesterday I did my re-cert class for MEWP and aerial lifts (there's four hours I won't get back), the instructor really emphasized situational awareness and understanding swing space (and clearance distances from MV/HV lines).

(Relevant to clearances- I manage a small Masonic building and we'd like to paint it but... 10' sidewalks and 12KV lines on both streets next to the building, the PoCo engineer I talked to about the voltage was stumped about how to do it legally without taking those lines out of service, which would Not Be Cheap.)

I wonder:


Probably not ready for prime time. But that report was from 6 years ago, so maybe the way to deal with personnel safety and those power lines is to keep people away from them and use a machine that can get the painting job done.
 
The building here next to city hall was a two phase building. It might still be for all I know. City Hall was designed so as never to cast a shadow upon it. Something to do with a birds of prey feeder up on that tall spire I think

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I got really curious and did some East coast research on Philly, emailed / called PECO, googled, and checked some PA PUC filings for upgrades they are doing while I am distracted waiting for another POCO here to get back to me LOL.
My hypothesis is they do infact have a 4kV 2-phase primary network in some legacy areas.
They would order one 13kV -> 4kv scott transformer made by Penn Transformer at each of several substations including 'Center City' 'OverBrook' and 'Upper Darby'.
The 4kv would be '3-wire two phase', and 'regular distribution transformers are used to make single phase 120/240 or 240/120 5-wire two phase'. The 4kv might also be used for 1phase light rail circuits for something called 'SEPTA' .
Funny thing about 'SEPTA' is get this they also run a 25hz network for them.
According to PUC filings the 4kv is being retired from 'OverBrook' and 'Upper Darby' and I would guess those existing two-phase customers will get scott-T's off the 13kv network.
I am no distribution engineer, not sure that even makes any sense or how it even works, but so far it seems logical.
Perhaps a real PECO person is on here and can clarify.
 
This is some amazing (and not uncommon) topic drift-
The 4kv might also be used for 1phase light rail circuits for something called 'SEPTA' .
Funny thing about 'SEPTA' is get this they also run a 25hz network for them.
South Eastern Pennsylvania Transportation Authority. The light rail/trolleys/trolley-buses/subway are the usual <1kv DC, the "regional" heavy rail are old Reading RR lines at 12kv 25Hz, same as Amtrak's (ex Penn RR) northeast corridor and Harrisburg lines although the systems are not interconnected. Got to get the power from somewhere... SEPTA has a converter station and switchyard at Wayne Junction to feed the entire system; PECO delivers 230kv and SEPTA takes it from there on their own network, a great thing about owning a railroad is being able to run your power along the R-O-W.

According to PUC filings the 4kv is being retired from 'OverBrook' and 'Upper Darby' and I would guess those existing two-phase customers will get scott-T's off the 13kv network.
Since AFAIK PECO hasn't made 2-phase in quite a while, all of their customers would be served by a Scott-T somewhere, could be in a substation or could be under the sidewalk.
 
Pennsylvania State Hospital at Byberry Farms had a 2 phase power plant in the boiler house that was capable of powering the whole place. From what I understand it was staffed by patients


1765421428692.png

It was over 60 buildings on over 1000 acres and at it's peak housed about 7000 patients

1765421808333.png
  • A- Laundry (S-8)​
  • B- Garages​
  • C- Warehouse​
  • D- Power Plant​
  • E- Nurses' Quarters (S-10, now Self Help)​
  • F- Electrical Substation​
  • G- C-1​
  • H- C-2​
  • I- C-3​
  • J- C-4​
  • K- C-5​
  • L- C-6​
  • M- Old Administration​
  • N- Old Cafeteria/Maintenence​
  • O- C-14 Infirmary​
  • P- Remains of old Laundry (C-13)​
  • Q- C-12​
  • R- Furey Ellis Hall​
  • S- C-11​
  • T- C-10​
  • U- C-9​
  • V- C-8​
  • W- C-7​
  • X- N-10 (TB Hospital)​
  • Y- N-8 (Max Security Female)​
  • Z- N-9 (Max Security Male)​
  • 1- W-6​
  • 2- W-7​
  • 3- W-3 (Active Therapy Building)​
  • 4- W-5 (Cafeteria/Dietary)​

It was coal fired and had it's own rail siding for coal deliveries

All gone now. Geppert Brothers tore it all down about 20 years ago. When I was a teen we used it for "urban exploration" but back then it was called "having a keg party"
 
South Eastern Pennsylvania Transportation Authority. The light rail/trolleys/trolley-buses/subway are the usual <1kv DC, the "regional" heavy rail are old Reading RR lines at 12kv 25Hz, same as Amtrak's (ex Penn RR) northeast corridor and Harrisburg lines although the systems are not interconnected. Got to get the power from somewhere... SEPTA has a converter station and switchyard at Wayne Junction to feed the entire system; PECO delivers 230kv and SEPTA takes it from there on their own network, a great thing about owning a railroad is being able to run your power along the R-O-W.
1765423062241.png

I believe there are still rotary converters at The Port Richmond Generating Station to supply The Northeast Corridor with 25Hz
 
Just yesterday I did my re-cert class for MEWP and aerial lifts (there's four hours I won't get back), the instructor really emphasized situational awareness and understanding swing space (and clearance distances from MV/HV lines).

(Relevant to clearances- I manage a small Masonic building and we'd like to paint it but... 10' sidewalks and 12KV lines on both streets next to the building, the PoCo engineer I talked to about the voltage was stumped about how to do it legally without taking those lines out of service, which would Not Be Cheap.)
O
 
Pennsylvania State Hospital at Byberry Farms had a 2 phase power plant in the boiler house that was capable of powering the whole place. From what I understand it was staffed by patients


View attachment 2581033

It was over 60 buildings on over 1000 acres and at it's peak housed about 7000 patients

View attachment 2581034
  • A- Laundry (S-8)​
  • B- Garages​
  • C- Warehouse​
  • D- Power Plant​
  • E- Nurses' Quarters (S-10, now Self Help)​
  • F- Electrical Substation​
  • G- C-1​
  • H- C-2​
  • I- C-3​
  • J- C-4​
  • K- C-5​
  • L- C-6​
  • M- Old Administration​
  • N- Old Cafeteria/Maintenence​
  • O- C-14 Infirmary​
  • P- Remains of old Laundry (C-13)​
  • Q- C-12​
  • R- Furey Ellis Hall​
  • S- C-11​
  • T- C-10​
  • U- C-9​
  • V- C-8​
  • W- C-7​
  • X- N-10 (TB Hospital)​
  • Y- N-8 (Max Security Female)​
  • Z- N-9 (Max Security Male)​
  • 1- W-6​
  • 2- W-7​
  • 3- W-3 (Active Therapy Building)​
  • 4- W-5 (Cafeteria/Dietary)​

It was coal fired and had it's own rail siding for coal deliveries

All gone now. Geppert Brothers tore it all down about 20 years ago. When I was a teen we used it for "urban exploration" but back then it was called "having a keg party"
I drive thru the road on North side. They kept a few of the old office buildings. My neighbor was a head nurse on second shift for years while I was a kid.While working second shift at the old Whitman's Chocolate plant not far from there the security guard called them to say one of their patients was in the lobby. Told him nobody was missing & a little while later a second patient sat in the lobby because but was a cold night and they were in thin PJ's. Guard called back and told then he now has two of their nuts in the lobby. Within five minutes they came by to take them back. We felt sorry for them and gave them some fresh made candy to eat.
 
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