Keyboard Shortcuts
ctrl + shift + ? :
Show all keyboard shortcuts
ctrl + g :
Navigate to a group
ctrl + shift + f :
Find
ctrl + / :
Quick actions
esc to dismiss
Likes
Search
AC Breaker panels... sub panels... Electrical codes, etc.
|
pentalab
--- In ham_amplifiers@..., "Phil Clements" <philc@...>
wrote: ifI looked. In our breaker box, all the ground wires and all the used asthere were two bus bars that are connected by a bus-wire? a sub-panel, you need seperate bus bars for the neutrals andgrounds with a removable shorting strap between the two. Only in the maintogether. I guess a few bucks are saved by leaving out the strap andinsulation for the two bus bars if one has no intention of ever changing amain panel over to a sub-panel.### This is correct. Only SUB-panel's are wired for separate grnd/neutral buss's.... via the shorting strap. I installed a 100 A sub panel... and such is the case. The reason is... they want any fault current to flow through the GRND buss bar... back to main panel.... and NOT the neutral. I'm talking about a hot to chassis short only... inside the HV supply/amp/ anything else. This requires by the electrical code... to have a separate GRND wire from sub panel to HV supply/amp CHASSIS. Of course their is also a grnd wire tying the main and sub panel together. ### any short from hot to neutral... in the HV supply/amp/anything else including sub panel itself... and fault current will flow back through the neutral.... back to main panel. ### This applies to any HV supply/linear amp as well. The neutral if used.... is fed to it's own separate buss bar/termination in the HV supply/amp...... and the neutral is NEVER bonded to the chassis. If u did... u would have any and all devices operating on 120 vac...having their return current flowing back to sub panel via GRND. And since the sub panel has isolated grnd/neutral buss's..... this 120 vac current would continue back to MAIN panel ..VIA the grnd wire tying the sub and main panel together. ### IE: The grnd wire[s] only are designed to carry FAULT current.... and NEVER normal operating current. ### When Rich or anybody else advocates bonding the Neutral to the chassis in any HV amp/RF deck/anything else... BEWARE... you are violating the electrical code in all 50 states, and all of Canada. ### The shorting strap used in main panel is heavy ga copper bar... and never wire. .... used to bond neutral buss and grnd buss's together. [it might have to handle 100+ A] I have never seen any panel yet, without isolated neutral and gnrd buss's. That's cuz with isolated grnd/neutral buss's..... any panel can be used as a main OR sub panel. Later... Jim VE7RF (((73))) |
|
craxd
--- In ham_amplifiers@..., "pentalab" <jim.thomson@...>
wrote: the differentNeutral wire connecct in one bus bar. How would it be ifwantused asthere were two bus bars that are connected by a bus-wire? any fault current to flow through the GRND buss bar... back to Correct, even though in reality, they tie together at the main panel. The way it used to be, all the breaker boxes used for a service main (main panel), like a 200 amp service in residential construction, have a common bus bar for both the neutral and ground. This bus bar is also bonded to the cabinet. These are the same as you will buy at Lowes and Home Depot. When you want a sub panel, you ask for and buy a sub panel as they're two different beasts. A sub panel could be used as a main panel, but both bus bars (ground and neutral) have to be tied together. Most sub panels though generally have a lower current rating like 100 amps or less. I guess you could buy them larger, but generally in residential construction, the sub panel is smaller than the main panel. I don't know of any houses being built today that use less than a 200 amp main. They used to have 100 amp mains like this house had before I changed it out. I put in a heat pump back in 1989 and had to upgrade to a 200 amp.
Correct. What Rich is saying is that since the ground and neutral tie together at the main, they still in reality are the same wire. The difference is that the neutral carries operating current back to the main, and back to the C.T. of the transformer. Since the neutral carries current, it's insulated. The ground though, being bare, is used for safety and shouldn't have but a momentary fault current flow in it. If a break in the hots insulation was to occur inside the cable jacket, it should possibly (HOPEFULLY) short to the bare ground and the fault current kick the breaker. That's why armored BX cable is better than Romex. Since the bare ground is bonded to the steel outlet or pull boxes, a short from the hot to a box will cause a fault current to travel through the ground wire, back to the main, and trip the breaker. The bare ground should be connected to the chassis of the amp so that if a short happens between the chassis and the hot (shorted transformer), the fault current will flow through the ground wire, back to the main, and trip a breaker. The NEC figures that the neutral is a current carrier and so it's insulated, and the ground is only a temporary fault current carrier. New TV sets throw this out the door as they all have a hot chassis any more. The fault current goes back through the neutral if the fuse don't blow. Here, the C.T on a lot of transformers at the pole go to a ground rod at the pole. The home also has a ground rod going to the ground/ neutral bus bar. Water pipes are not a good ground since most tap on to the main water line via pvc pipe anymore, via a high pressure fitting. Same goes for a well which uses PVC pipe. If the copper water lines attached directly to a cast iron water main, it would be pretty good. Most water mains here are thick wall, large ID plastic anymore. You also would have a meter to feed through where a bond jumper would need to be put across it. The water itself is not that good of a conductor for a ground.
See above. It's so you don't have operating current on a bare ground wire. And since the sub panel has isolated grnd/neutral buss's..... this 120 vac current wouldand main panel together. Correct!
Here, you used to either buy a sub panel or a main panel. My Square D main panel has a common bus bar where a series of holes are up either side. There's two rows of set screws up the front over the holes. In it, you can have a ground right under a neutral. I just seen a single bus bar main panel by Square D at Lowes the other day while I was looking around. Your correct on a shorting jumper. It has to be able to handle the maximum current the box is rated at. For a main, I prefer the single bus bar. The proper way of running a 115/230 Vac circuit is to use either 10-3 or 8-3 etc romex. There you have a black, red, white, and bare ground. Black and Red are the two hots, White neutral, and bare is ground. A 230 Vac only circuit could be ran with say 10-2 or 8-2, but the white would have to be re-colored by tape or heat shrink to pass an inspection. In some areas, I'm not sure whether that would be acceptable as local building codes can differ. If using cordage like type SO cord, I always buy like 10-2 with black and red instead of white. It costs a little more, but to me worth it. Ground is always green in all. Some cordage like is being used in computer power cables though have blue and brown or black for the power if I recall, and green as ground. Grey 3-wire zip type cord can be used as it has no color except the green ground in the middle. This is similar to dryer pig tails, etc. I've used this cable to wire 60 amp fused disconnects for 225 amp welders (buzz boxes). The big heavy 230 vac cable for a heat pumps, etc main current is similar to service entry cable in a grey rubber jacket. The two hots are black with a bare ground. The wire is aluminum. I'm not for sure the current capacity of the stuff I have here though.
Best, Will |
|
On Nov 17, 2006, at 4:09 PM, pentalab wrote:
--- In ham_amplifiers@..., "Phil Clements" <philc@...>Beware of what? -- certainly not electric shock. In my breaker box, the neutral wires and the ground wires go into the same bus strip. When there's a fault, the breaker trips. ...R L Measures, AG6K, 805.386.3734 r@..., rlm@..., www.somis.org |
|
Rich & DJ
I have a question if I am legal by code rules. I bought this place 4
years ago and here is how it was wired. , I have my own 400 amp transformer on a utility pole in the yard, at the bottom of the pole there is a 3 phase 400amp disconnect with only two lines in use and fused. There is no 400A 240V disconnect standard so a 3 phase box was used, From there I have one run to the work shed and a 200 amp breaker box and another run to the home and a 200 amp breaker box. I have wondered about the splitting of the 400A run. The shed has my work shop and my radio room. In the shed I have a welder, air compressor, saws and future amp set up. I don't want to rewire more than I have to, to be safe. Right the 240v for the welder and air compressor is a 3 wire setup. All original wiring in the shed was done in conduit. The radio room has the breaker box in it so it will not be hard to rewire for an amp. I built a universal (variable voltage) power supply for the amp and it has a 3 wire cord from a range now. This place is out in the sticks with the hicks and the ticks so wiring was not inspected after it was first run. Rich, kd0zz: |
|
pentalab
--- In ham_amplifiers@..., R L Measures <r@...> wrote:
### This applies to any HV supply/linear amp as well. The RICH SEZ....Beware of what? -- certainly not electric shock.### I give up ! ### Why don't u take some of that 4 wire home depot 8 awg... and parallel em into 2 pairs.... eq ga is then 5ga. Then u will have all 4 wires carrying current... and can run ur 8171. Jim |
|
Robert B. Bonner
¿ªÔÆÌåÓýI don¡¯t know about using a 3Phase disconnect, but I don¡¯t see a problem personally.? Its pretty obvious whats happening inside the disco.? You wouldn¡¯t want to use 3phase panels this way. ? You don¡¯t have a problem code wise if the wiring going from the 400A pole fuses to each of the panels is 500MCM copper where it is then breakered to 200Amps. ? In a rural situation where the state inspector never sees it, most wouldn¡¯t do this.? If the wire is OO then the fuses in the 400A disconnect NEED to be 200A.? The wire must be fused at the source for the wire¡¯s max current. ? OO wire is rated at 190Amps however many locations allow OO to be fused at 200 AMPS in residential power service distribution, where I live is one of them.? Otherwise OOO copper would be required.? Aluminum conductors require 2X the size and I don¡¯t recommend aluminum unless absolutely necessary. ? So there you go, what do you have? ? From: ham_amplifiers@... [mailto:ham_amplifiers@...] On Behalf Of Rich & DJ
Sent: Saturday, November 18, 2006 9:32 AM To: ham_amplifiers@... Subject: RE: [ham_amplifiers] Re: AC Breaker panels... sub panels... Electrical codes, etc. ? I have a question if I am legal by code rules. I bought this place 4 years ago and here is how it was wired. , I have my own 400 amp transformer on a utility pole in the yard, at the bottom of the pole there is a 3 phase 400amp disconnect with only two lines in use and fused. There is no 400A 240V disconnect standard so a 3 phase box was used, From there I have one run to the work shed and a 200 amp breaker box and another run to the home and a 200 amp breaker box. I have wondered about the splitting of the 400A run. The shed has my work shop and my radio room. In the shed I have a welder, air compressor, saws and future amp set up. I don¡¯t want to rewire more than I have to, to be safe.? Right the 240v for the welder and air compressor is a 3 wire setup. All original wiring in the shed was done in conduit. The radio room has the breaker box in it so it will not be hard to rewire for an amp. I built a universal (variable voltage) power supply for the amp and it has a 3 wire cord from a range now. This place is out in the sticks with the hicks and the ticks so wiring was not inspected after it was first run. ? Rich, kd0zz:
|
|
FRANCIS CARCIA
You can split a 400 amp run but each pair of conductors should be sized to handle 400 amp fault current. The conductor needs to match the fuse or breaker that feeds it. Your sub panel is 200 amps so after that it only needs to be sized for 200 amps. Rich & DJ wrote:
|
|
FRANCIS CARCIA
240 400 A is a newer item so I'm not surprised someone used a 3 phase unit. A guy I work with looked into the 400 amp setup and changed his mind when he saw the price.? I used 0000 copper between my meter socket and panel about 4 feet away. I must have looked like a fool pulling that wire one strand at a time. I felt pretty stupid when I dropped the can of no ox down the conduit to the pole. I was lucky to have a knot in the pull rope and it popped right up without digging it up and cutting the pipe. "Robert B. Bonner" wrote:
|
You can split a 400 amp run but each pair of conductors should be sized to handle 400 amp fault current. The conductor needs to match the fuse or breaker that feeds it.Outside Feeder Tap of Unlimited Length Rule [240.21(B)(5) Outside feeder tap conductors can be of unlimited length without overcurrent protection at the point they receive their supply, but they must be installed in accordance with the following requirements: Figure 3 (1) The tap conductors shall be suitably protected from physical damage. (2) The tap conductors shall terminate at a single circuit breaker or a single set of fuses that limit the load to the ampacity of the conductors. This single overcurrent device shall be permitted to supply any number of additional overcurrent devices on its load side. (3) The overcurrent device for the tap conductors is an integral part of a disconnecting means or shall be located immediately adjacent thereto. (4) The disconnect is located at a readily accessible location either outside the building or structure, or nearest the point of entry of the service conductors. -- Eddie, WB4MLE |
|
On Nov 18, 2006, at 7:42 AM, pentalab wrote:
--- In ham_amplifiers@..., R L Measures <r@...> wrote:As well you should since there would likely be no more than 50v on the cabinet for under 2 seconds during a major short in the stove -- something I have yet to see in one.### This applies to any HV supply/linear amp as well. The And throw away the extant 4ga. wire? Then uI don't have an 4cx10,000A / 8171. I have the J version sitting around waiting until I finish the on-going slow-going solar-electric project. R L Measures, AG6K, 805.386.3734 r@..., rlm@..., www.somis.org |
|
Rich & DJ
Well I guess all is not good because the wire running to the house and
toggle quoted message
Show quoted text
the wire running to the shed are alum for 200 amp service each. I can see it in the disconnect where it is dual 200amp lines, then it goes underground , the conduit divides somewhere underground an feeds the two 200amp breaker boxes. The pole has a 380A commercial, 400A residential transformer. If I need heaver wire to my breakers then why do people in a subdivision not need a wire rated for the transformer on the pole? This had to be in place when it was first done because it can't be turned off at the meter. If you pull my meter, all is still hot. My meter runs off a current transformer. Just curious, not trying to question your statement, just trying to lean. -----Original Message-----
From: ham_amplifiers@... [mailto:ham_amplifiers@...] On Behalf Of Robert B. Bonner Sent: Saturday, November 18, 2006 10:28 AM To: ham_amplifiers@... Subject: RE: [ham_amplifiers] Re: AC Breaker panels... sub panels... Electrical codes, etc. I don't know about using a 3Phase disconnect, but I don't see a problem personally. Its pretty obvious whats happening inside the disco. You wouldn't want to use 3phase panels this way. You don't have a problem code wise if the wiring going from the 400A pole fuses to each of the panels is 500MCM copper where it is then breakered to 200Amps. In a rural situation where the state inspector never sees it, most wouldn't do this. If the wire is OO then the fuses in the 400A disconnect NEED to be 200A. The wire must be fused at the source for the wire's max current. OO wire is rated at 190Amps however many locations allow OO to be fused at 200 AMPS in residential power service distribution, where I live is one of them. Otherwise OOO copper would be required. Aluminum conductors require 2X the size and I don't recommend aluminum unless absolutely necessary. So there you go, what do you have? _____ From: ham_amplifiers@... [mailto:ham_amplifiers@...] On Behalf Of Rich & DJ Sent: Saturday, November 18, 2006 9:32 AM To: ham_amplifiers@... Subject: RE: [ham_amplifiers] Re: AC Breaker panels... sub panels... Electrical codes, etc. I have a question if I am legal by code rules. I bought this place 4 years ago and here is how it was wired. , I have my own 400 amp transformer on a utility pole in the yard, at the bottom of the pole there is a 3 phase 400amp disconnect with only two lines in use and fused. There is no 400A 240V disconnect standard so a 3 phase box was used, From there I have one run to the work shed and a 200 amp breaker box and another run to the home and a 200 amp breaker box. I have wondered about the splitting of the 400A run. The shed has my work shop and my radio room. In the shed I have a welder, air compressor, saws and future amp set up. I don't want to rewire more than I have to, to be safe. Right the 240v for the welder and air compressor is a 3 wire setup. All original wiring in the shed was done in conduit. The radio room has the breaker box in it so it will not be hard to rewire for an amp. I built a universal (variable voltage) power supply for the amp and it has a 3 wire cord from a range now. This place is out in the sticks with the hicks and the ticks so wiring was not inspected after it was first run. Rich, kd0zz: |
|
Robert B. Bonner
¿ªÔÆÌåÓýThe power company is the other side of the world¡? ? I take everything I say back.? I¡¯m understanding what you have setup better understood¡? I had the same thing at my farm. ? Is the Disconnect on the pole fused or just a disconnect?? The wire going to the house and garage/barn are just fine. ? The power feeding your house is just power company (even if you supplied it)? wiring.? This is just fine as long at it doesn¡¯t go more than 5 feet inside your house before hitting the breakers.? It doesn¡¯t need to be fused as it is service wiring. ? Sorry for blasting off the first post.? It was the first thing I did this AM, got up at 10:15¡? I have a Bar schedule¡ ? BOB DD ? From: ham_amplifiers@... [mailto:ham_amplifiers@...] On Behalf Of Rich & DJ
Sent: Saturday, November 18, 2006 4:42 PM To: ham_amplifiers@... Subject: RE: [ham_amplifiers] Re: AC Breaker panels... sub panels... Electrical codes, etc. ? Well I guess all is not good because the wire running to the house and the wire running to the shed are alum for 200 amp service each. I can see it in the disconnect where it is dual 200amp lines, then it goes underground , the conduit divides somewhere underground an feeds the two 200amp breaker boxes. The pole has a 380A commercial, 400A residential transformer. If I need heaver wire to my breakers then why do people in a subdivision not need a wire rated for the transformer on the pole? This had to be in place when it was first done because it can¡¯t be turned off at the meter. If you pull my meter, all is still hot. My meter runs off a current transformer. Just curious, not trying to question your statement, just trying to lean. ? -----Original Message----- ? I don¡¯t know about using a 3Phase disconnect, but I don¡¯t see a problem personally.? Its pretty obvious whats happening inside the disco.? You wouldn¡¯t want to use 3phase panels this way. ? You don¡¯t have a problem code wise if the wiring going from the 400A pole fuses to each of the panels is 500MCM copper where it is then breakered to 200Amps. ? In a rural situation where the state inspector never sees it, most wouldn¡¯t do this.? If the wire is OO then the fuses in the 400A disconnect NEED to be 200A.? The wire must be fused at the source for the wire¡¯s max current. ? OO wire is rated at 190Amps however many locations allow OO to be fused at 200 AMPS in residential power service distribution, where I live is one of them.? Otherwise OOO copper would be required.? Aluminum conductors require 2X the size and I don¡¯t recommend aluminum unless absolutely necessary. ? So there you go, what do you have? ? From: ham_amplifiers@ ? I have a question if I am legal by code rules. I bought this place 4 years ago and here is how it was wired. , I have my own 400 amp transformer on a utility pole in the yard, at the bottom of the pole there is a 3 phase 400amp disconnect with only two lines in use and fused. There is no 400A 240V disconnect standard so a 3 phase box was used, From there I have one run to the work shed and a 200 amp breaker box and another run to the home and a 200 amp breaker box. I have wondered about the splitting of the 400A run. The shed has my work shop and my radio room. In the shed I have a welder, air compressor, saws and future amp set up. I don¡¯t want to rewire more than I have to, to be safe.? Right the 240v for the welder and air compressor is a 3 wire setup. All original wiring in the shed was done in conduit. The radio room has the breaker box in it so it will not be hard to rewire for an amp. I built a universal (variable voltage) power supply for the amp and it has a 3 wire cord from a range now. This place is out in the sticks with the hicks and the ticks so wiring was not inspected after it was first run. ? Rich, kd0zz:
|
|
FRANCIS CARCIA
All you need to do is add a pair of 200 amp breakers in series with each run and you will be legal. The only 400 amp run needs to be between the 400 amp breaker and the two 200 amp units.
toggle quoted message
Show quoted text
Rich & DJ wrote:
|
|
hbmandel
Size 3/0 AWG wire is the correct guage to use for 200 ampere service,
not 2/0 AWG. In any circumstance the wire diameter needs to be sized to the breaker protecting it. In a dead short situation you will want the breaker opening, even if it is rated at 125 to 150 percent tripping, well before the wire heats up to the point where the insulation melts and possibly catches fire or releases poisonous gases. The only point where the a.c. electrical ground is bonded to the neutral should be in the main distribution panel and not in any sub panel or appliance. In commercial 200 amp single-phase, three wire installations the size of the a.c.e.g. is 2AWG while the current-carrying conductors are 3/0 AWG. This is because the a.c.e.g. is a fault drain and not a current- carrying conductor, but in D.C., everything changes, and that is a topic for a separate discussion. Lastly, in amateur appliances such as medium power transmitting equipment, the connection to the frame of the equipment, e.g., the frame ground or RF static drain, should be of the heaviest guage affordable, and this conductor needs to be bonded to all the other a.c.e.g and static grounds, ground rods, external ground ring, interior halo, etc. Hal Mandel W4HBM |
|
Robert B. Bonner
Hal I don't take everything back.
toggle quoted message
Show quoted text
We've been talking residential services here not commercial. The actual current ampacity for 2/0 copper is 190 amps but it is allowed to be fused to 200 for Residential Service Feeds only in many cities. 2/0 copper is acceptable in way over 1/2 of the cities in the country for feeding a 200 amp RESIDENTIAL SERVICE. In the other half they require 3/0. You must check your locality when pulling a 200 amp service. They operate in the 5% grey area. 3/0 copper is required in commercial services. Sioux Falls, SD is one of those towns where 2/0 copper is acceptable for service feeds. Minneapolis where I worked as an electrician in the mid 80's was another. Do not confuse COMMERCIAL SERVICES with Residential Services... It's like comparing Apples and Oranges can't be done. So what do we have here? We have the NEC and most cities are dead locked on the code by legislation. Others fly by the seat of their pants in other areas. What I don't like is here while we can pull 2/0 when we change out a service we are required by city ordinance to UPDATE our houses to the current code everywhere else. This means ARC FAULT circuits in the bedrooms (which I haven't done yet) and Ground Fault breakers or outlets in the kitchens, laundry and bathrooms. This house of mine was built in 1962 with a 60 amp service. Many of the rooms just had barely 2 outlets. Fortunately the past owner updated to a 20 circuit 100 A panel in 1972 and added the required circuits in the kitchen and baths. The first thing I did, like the first week was rehung a new 30 circuit 100 amp panel so I could even hook up some radio without blinking every light in the place. I've since installed a 200 Amp service panel with 40 circuits (5 - 30 amp 220's to the radio room, plus a 30 amp 120 that feeds the 24 outlets in the radio console) The basement is wired to the max all the way to code and broken up nicely. I think I have 4-5 circuits left in that panel. The garage has a 100 Amp sub panel with the hot tub 50 ground fault sub panel off of it, the RV 50 amp ground fault circuit, lighting, garage power, a 30 amp garage 220 incase I need to test an amp or something, 2 - 20 amp each side of the garage door block heater plugins for the diesel truck, etc.. All ground fault where outlets are, plus a panel outlet. OH yeah, the Meter Sequence here needs to be a METER MAIN, where the actual main breakers are in the meter box. This is because it is 20 feet through an addition before my main panel in the basement. That meter main has room for 8 - 220 breakers. I figure I will light up the yard from there TIM ALLEN with his Christmas Lights. If I ever do build that 30 x 40 garage I will probably put in a 400 amp panel out there and sub feed the house. That 200 Amp service is pretty busy. Convenience is nice, but if I cranked up everything here I would have to call the POWER COMPANY and tell them to pull the BORON RODS out of the reactor another inch... BOB DD -----Original Message-----
From: ham_amplifiers@... [mailto:ham_amplifiers@...] On Behalf Of hbmandel Sent: Saturday, November 18, 2006 7:32 PM To: ham_amplifiers@... Subject: [ham_amplifiers] Re: AC Breaker panels... sub panels... Electrical codes, etc. Size 3/0 AWG wire is the correct guage to use for 200 ampere service, not 2/0 AWG. In any circumstance the wire diameter needs to be sized to the breaker protecting it. In a dead short situation you will want the breaker opening, even if it is rated at 125 to 150 percent tripping, well before the wire heats up to the point where the insulation melts and possibly catches fire or releases poisonous gases. The only point where the a.c. electrical ground is bonded to the neutral should be in the main distribution panel and not in any sub panel or appliance. In commercial 200 amp single-phase, three wire installations the size of the a.c.e.g. is 2AWG while the current-carrying conductors are 3/0 AWG. This is because the a.c.e.g. is a fault drain and not a current- carrying conductor, but in D.C., everything changes, and that is a topic for a separate discussion. Lastly, in amateur appliances such as medium power transmitting equipment, the connection to the frame of the equipment, e.g., the frame ground or RF static drain, should be of the heaviest guage affordable, and this conductor needs to be bonded to all the other a.c.e.g and static grounds, ground rods, external ground ring, interior halo, etc. Hal Mandel W4HBM Yahoo! Groups Links |
|
pentalab
--- In ham_amplifiers@..., R L Measures <r@...> wrote:
#### The above was a joke. IMO ur 100' length [200' loop] ofRICH SEZ...And throw away the extant 4ga. wire?### Why don't u take some of that 4 wire home depot 8 awg...and parallel em into 2 pairs.... eq ga is then 5ga. 4 ga wire is WAY too small for a 4x10. 4 ga wire isn't even rated to handle 110 A.....never mind the 4-6 x that current.... every 8.3 msecs. Calculate the PEAK current drawn from the plate xfmr pri on a huge C input HV supply... and you will see why I use big everything, including wire, contactor's, etc.... from 200 A main panel to pri of 253 lb Dahl plate xfmr. Duncan's pwr supply modeler.. PSUD-2 comes in handy for this stuff. It also has 2 x methods of calculating plate xfmr pri IMPEDANCE. Z is used to calculate peak pri current drawn... not simply plate xfmr pri dc resistance. #### 3/000 CU from main 200A panel to HV supply is what's really needed. Snip a few strands to make it fit the 100 A breaker at EACH end. later... Jim VE7RF |
|
pentalab
--- In ham_amplifiers@..., "Robert B. Bonner"
<rbonner@...> wrote: If I ever do build that 30 x 40 garage I will probably put in a 400amp panel out there and sub feed the house. That 200 Amp service is pretty busy. ### My electrician buddy said 240V 400A service was available...and "no sweat". 400 A = 96 Kva ! 200A = 48 Kva. I still don't get it. I have "200 A service".... and SO do my 15 neighbours... all hanging from the SAME 50 Kva pole pig ! Some of my neigbours have a secondary suite in their homes... with a 2nd elctric stove, etc. ### since we all got natural gas back in 1992... most of the electric hot water tanks and oil furnaces have gone bye bye... reducing the overall load..a bit. I still don't see any natural gas clothes dryers..yet. Back East, they all have em... plus gas ranges. My hot water tank, fireplace, and furnace all run on natural gas. ### Bottom line is... when I smoke the pole pig at dinner time one night..... I guess I can just whine to the pwr co... and say .."I'm supposed to be getting 200A CCS service... so where is it? " ### The biggest pole mount pole pig I have seen is 100 KVA. But these were special one off units...designed to drop 25 kv down to 12.5 kv..... then 12.5 kv into our vault xfmr at work... where the vault xfmr dropped it again to 208/120. This is all 3 phase... and both the 3 x old 75 kva xfmr's.. and the 3 x new 100 kva xfmr's are huge... when u see em on the grnd. Every time I see 3 x 75/100 kva xfmr's.. all on the same pole, I cringe........ the weight is massive.. as in 2 tons. ### anything above 100 KVA per phase... and it then goes on the grnd. Later... Jim VE7RF |
|
On Nov 19, 2006, at 5:13 AM, pentalab wrote:
--- In ham_amplifiers@..., R L Measures <r@...> wrote:Jim -- Do you design your amplifiers for A0 or for SSB?#### The above was a joke. IMO ur 100' length [200' loop] ofRICH SEZ...And throw away the extant 4ga. wire?### Why don't u take some of that 4 wire home depot 8 awg...and parallel em into 2 pairs.... eq ga is then 5ga. 4 ga wire isn'tWouldn't a 900-pounder be better? Duncan's pwr supply modeler.. PSUD-2 comes in handy forI did the calculations for the 8170 amplifier with Ohm's Law. The calc. peak mains current was c. 300A. The measured result was 1200v- pk into 50-ohms on SSB. R L Measures, AG6K, 805.386.3734 r@..., rlm@..., www.somis.org |
|
hbmandel
Bob,
Who is asking for any retractions? I didn't say to wire anything a certain way, just pointed out the constraints I face and the considerations given when we wire up something under the NEC code here. I know you're lying: Ha, ha! I've seen your QTH. You've got knob and tube wiring with knife switches and bare aluminum #16 AWG on ceramic nailed-in insulators on the studs. (I'm just pulling your leg, here, Bob. Your house will probably not burn down from octopuses.) In Kentucky I installed an Appleton plug for the gen set on the side of the house (200 A) and ran a battery charging outlet with a twist- loc right above it. However, inside, it's a different story. No ATC, just two different breakers. I didn't want the gen set kicking in when I wasn't home: Lemme decide on my own. As for the shack, I run 60 foot 10/3 SOOW cords on four different circuits from the sub panel, right through the laundry room and around the office to the bench. All the grounds and grounding goes through a wall-mounted MGB that has a 4/0 green stranded going right out to the SAGB and everything is bonded. I'm afraid to tear into the walls. I don't know what I'll find. The gen set's wired similarly: The 4X2 AWG is an SOOW cord, but the frame is directly bonded to the EGR with a dedicated rod right off the porch. We already have an old washing tub on the porch, and a 10 cent Coke machine from the year Gimel, so the gen set fits right in with the Tobacco Road decor. Hey, it's Eastern Kentucky. The main antenna disconnect switch is from a friend's house in Elmira where he yanked the K&T wiring when he renovated. Ceramic, brass, 5/8 blades: a beauty from 1900. See ya! Hal |
|
FRANCIS CARCIA
We had a 37 KVA unit here to support 6 houses. one hot?night when it?popped? they hung a 50 KVA
toggle quoted message
Show quoted text
pentalab wrote:
|
to navigate to use esc to dismiss