Home Electrical Wiring

[grumpy_old_retired]

Can someone explain to a "dumb novice’’ (ME) how to get a 100Amp service from an Electric Meter (attached to a pole) that has the following: 220v 15A (45A) 2 wire.

Q. How can I wire a home for 100Amp when all meters I see have 15A (45A) service?

Q. How do you ground the meter?

Q. How can I have a service panel with 6 circuit breakers covering the 100Amp requirement when meter shows 15A (45A)?

Q. Does Thailand Electric supply/support 100Amp service?

Q. I have to make the assumption that I would need a 100A electric meter?

Q. What does 15A (45A) mean?

I realize that some. if not all these questions, are stupid to some of you but I am at a loss as to what I need as to an Electric Meter and Service Panel for 100Amp service. Any help would be appreciated.

[chownah]

Go to the electricity office and arrange to pay some money and have your meter upgraded so you can get 100 amps....I can't remember if its a 30A (100A) or if its 45A (100A).....but they've got 'em unless they just ran out....

Chownah

[Crossy]

Can someone explain to a "dumb novice’’ (ME) how to get a 100Amp service from an Electric Meter (attached to a pole) that has the following: 220v 15A (45A) 2 wire.

Q. How can I wire a home for 100Amp when all meters I see have 15A (45A) service?

Q. How do you ground the meter?

Q. How can I have a service panel with 6 circuit breakers covering the 100Amp requirement when meter shows 15A (45A)?

Q. Does Thailand Electric supply/support 100Amp service?

Q. I have to make the assumption that I would need a 100A electric meter?

Q. What does 15A (45A) mean?

I realize that some. if not all these questions, are stupid to some of you but I am at a loss as to what I need as to an Electric Meter and Service Panel for 100Amp service. Any help would be appreciated.

Never a stupid question when it comes to electrics

OK, do you REALLY need a 100A supply, that's in the order of 22kW of power? If you DO need that sort off oomph get a 3-phase connection

You don't ground the meter, you have a ground bar in the distribution board and connect your outlets to that. The ground bar goes to an earth stake and possibly an MEN link to the incoming neutral.

The breakers protect the circuit they switch, it's not unusual to have your breakers adding up to more than the supply fuse. I'm sure Elkangorito will go into load calculations etc

AFAK the 15/45 on the meter implies you have a supply capable of about 45A probably fused at 60A.

Once again, do you really need 100A? A clue as to the size of your house and exactly what you're powering would help a lot

and YES, you can get a 100A supply, BUT you may be asked to buy transformer if the local one isn't big enough

Edited February 8, 2007 by Crossy

[GuestHouse]

I doubt very much that you are using anywhere near 100A in your house.

The fuses, or more commonly these days, circuit breakers are selcted to protect the cicuit they feed. So a 10A fuse might be used on a ring main where the maximum current drawn could be as high as 10A.

The wiring for that circuit will be selected to be able to withstand 10A - But it is unlikely that you draw 10A on the circuit.

Repeat this for each circuit and it becomes clear that the sum of all the 'Fuse/Circuit Breaker Ratings' can add up to more than the supply rating.

For this reason we have a main supply fuse/breaker that will be set at below the Supply Company Rating for the feed to the house.

CAUTION

Don't be tempted to ask for two feeds from two different meters. This can be done, but if the meter feeds are taken off two differnt 'phases' either when they are first installed or at any time in the future when maintenance is done. Then you could be at risk of having extremely high voltages in your house.

[Somtham]

Q. What does 15A (45A) mean?

AFAK the 15/45 on the meter implies you have a supply capable of about 45A probably fused at 60A.

I've seen this question pop up several times so I talked to the guys at the electric company and they told me that the meter is rated continuously for 15 amps with overload protection up to 45 amps.

Agree, 100 amps is a lot. What are you powering?

[elkangorito]

CAUTION

Don't be tempted to ask for two feeds from two different meters. This can be done, but if the meter feeds are taken off two differnt 'phases' either when they are first installed or at any time in the future when maintenance is done. Then you could be at risk of having extremely high voltages in your house.

Can you please explain how & why this can happen?

[Tywais]

Some detailed information on 3-phase systems and efficiency.

http://www.3phasepower.org/

http://www.answers.com/topic/three-phase-electric-power

http://www.3phasepower.org/3phasetransformers.htm

And single phase > http://en.wikipedia.org/wiki/Single_phase_electric_power

[Tywais]

CAUTION

Don't be tempted to ask for two feeds from two different meters. This can be done, but if the meter feeds are taken off two differnt 'phases' either when they are first installed or at any time in the future when maintenance is done. Then you could be at risk of having extremely high voltages in your house.

Can you please explain how & why this can happen?

I suspect he is suggesting if you bring in two phases you have the potential (pun - sorry) to have 380 volts if wired at the sockets incorrectly.

[elkangorito]

CAUTION

Don't be tempted to ask for two feeds from two different meters. This can be done, but if the meter feeds are taken off two differnt 'phases' either when they are first installed or at any time in the future when maintenance is done. Then you could be at risk of having extremely high voltages in your house.

Can you please explain how & why this can happen?

I suspect he is suggesting if you bring in two phases you have the potential (pun - sorry) to have 380 volts if wired at the sockets incorrectly.

380 volts is not "extremely high voltage".

Anyway, there is nothing wrong with using 2 or 3 Kilowatt Hour meters in multiphase installations. As a matter of fact & for domestic/commercial installations, you'll only see this arrangement. Why? Because power consumption is more accurately measured when 1 kilowatt hour meter is used per phase.

Also, it is highly unlikely that you will be able to get only 2 phases connected to your premises because Thailand uses a 3 phase 4 wire system. Supplying only 2 phases per installation would induce greater out-of-balance currents within the electrical system. This is an undesirable effect.

So, I'd still like to find out about this "extremely high voltage".

[Tywais]

380 volts is not "extremely high voltage".

So, I'd still like to find out about this "extremely high voltage".

I fully agree, just depends on one's experience I would guess. For example, at our laboratory we have systems that operate between 150kV to 450kV - even now I consider them just 'high voltage'. I also operate another device in the neighborhood of 2 Mega Volts. By definition anything over 1kV would be high voltage. No real definition for 'extremely high voltage'.

[elkangorito]

Just checking AS/NZ 3000:2000 wiring rules, which say the following;

Extra Low Voltage (ELV) - Less than 50 volts A.C. or less than 120 volts ripple free D.C.

Low Voltage (LV) - greater than ELV but less than 1000 volts A.C. or 1500 volts D.C.

High Voltage (HV) - Exceeding LV.

[GuestHouse]

Oh I see I've trodden on someone's toes.

(What is it with Sparkies that they believe only they have the 'knowledge').

QUOTE(GuestHouse @ 2007-02-08 19:34:16)

CAUTION

Don't be tempted to ask for two feeds from two different meters. This can be done, but if the meter feeds are taken off two different 'phases' either when they are first installed or at any time in the future when maintenance is done. Then you could be at risk of having extremely high voltages in your house.

Can you please explain how & why this can happen?

Yes, quite easy, either at the time of installation or during later maintenance some half wit connects feeds from different phases to the meters.

380V not extremely high voltage.

It is an extremely high voltage if

A) Your installation is designed for 220/240

Your appliances are designed for 220/240

C) You happen to have it running through you.

But if you want to argue about the definition of 'Extremely High' do so, some people get off on pedantry.

What is important is the OP understands their is a safety issue relating to multiple feeds being brought into his home.

Having found several instances in Thailand of fused systems where the main feeder fuse is placed in the Neutral line I'm inclined to the view that if it can be messed up it will be.

Edited February 9, 2007 by GuestHouse

[chownah]

Grumpy old retired,

Just so you don't get lost in the twists and turns of the discussion I just want to be sure that you know that if you want to get a 100 amp meter so you can run a 100 amp main panel then what you need to do is to talk with the electric company.

If others disagree with this I'm sure they will speak up.

Chownah

[Silurian]

I looked at the meter outside of my townhouse and it is rated 45(100). I just put in new electrical wiring recently and upgraded the main panel from 32A to 100A. The sister-in-laws house next door has the old 32A main and it trips when more than three AC units are on at the same time which can happen often in a house with 4 people. I don't think I will ever need 100A but I wanted something higher than 32A.

Back in the US, the last two houses I lived in I believe had 100A mains.

[lopburi3]

I looked at the meter outside of my townhouse and it is rated 45(100). I just put in new electrical wiring recently and upgraded the main panel from 32A to 100A. The sister-in-laws house next door has the old 32A main and it trips when more than three AC units are on at the same time which can happen often in a house with 4 people. I don't think I will ever need 100A but I wanted something higher than 32A.

Back in the US, the last two houses I lived in I believe had 100A mains.

Yes but in the US that 100 amps would only be about 50 amps here when you convert power (VA).

I use a 15/45 meter service and have 5 air conditioners (4 normally used at night) and 5 refrigerations running. Have 10 people living in house so multi use of water heaters is often the case. The meter does spin rather fast but have not have any failure.

[chownah]

I looked at the meter outside of my townhouse and it is rated 45(100). I just put in new electrical wiring recently and upgraded the main panel from 32A to 100A. The sister-in-laws house next door has the old 32A main and it trips when more than three AC units are on at the same time which can happen often in a house with 4 people. I don't think I will ever need 100A but I wanted something higher than 32A.

Back in the US, the last two houses I lived in I believe had 100A mains.

Yes but in the US that 100 amps would only be about 50 amps here when you convert power (VA).

I use a 15/45 meter service and have 5 air conditioners (4 normally used at night) and 5 refrigerations running. Have 10 people living in house so multi use of water heaters is often the case. The meter does spin rather fast but have not have any failure.

I think that US panels are rated at 220 volts so actually a 100 amp panel in the US can supply about the same power as a 100 amp panel here.

Chownah

[Tywais]

I think that US panels are rated at 220 volts so actually a 100 amp panel in the US can supply about the same power as a 100 amp panel here.

Chownah

110-115 rated as lop mentions.

[chownah]

I think that US panels are rated at 220 volts so actually a 100 amp panel in the US can supply about the same power as a 100 amp panel here.

Chownah

110-115 rated as lop mentions.

Nope, a 200 amp main panel in the US can provide 200 amps 220 volts.

Chownah

P.S. Have you found out yet the geometry for the ion containment field?.....Chownah

Edited February 10, 2007 by chownah

[Crossy]

I think that US panels are rated at 220 volts so actually a 100 amp panel in the US can supply about the same power as a 100 amp panel here.

Chownah

110-115 rated as lop mentions.

Nope, a 200 amp main panel in the US can provide 200 amps 220 volts.

Chownah

P.S. Have you found out yet the geometry for the ion containment field?.....Chownah

Just clarify for me chaps

A US 100A supply gives 2 x 100A @ 110V as a bi-phase 110-0-110, so you get 220V for big appliances from the two live wires, yes??

So it's actually roughly equivalent to a 220V 100A single phase supply then ?

[lopburi3]

It's been 40 years but believe the panels are marked as 100 (200) amp for 100 amp service as the US uses split phase so there are two hot lines coming in at 110 volts each and each will be capable of providing 100 amps. They can be combined to provide 208v for stoves/heaters and such. With heating and cooking almost all electric these days the requirements are often a lot higher than here in Thailand (luckily as the cost is sure not going down).

[chownah]

Every main panel I've seen in the US (not counting the old fashioned ones using fuses) has a double pole breaker for the main breaker and it has the two hot service wires connected to it. Double pole breakers are 220V breakers in the US and single pole breakers are 110V breakers. This is one indication that the panel can supply its main breaker rating at 220V....because the main breaker is a 220V breaker....so...that means that a 100 amp service will have a 100 amp panel and in the 100 amp panel the main breaker will be a double pole breaker which means it is a 220V breaker and it will have a trip current of 100 amps.

Chownah

[grumpy_old_retired]

Thanks to all for answering my questions - chownah, crossy, lopburi3, elkangorito.

I tried to attach an electrical drawing for the house I plan to build but boongled that job as well!

To answer the questions: 3 bedrooms, 2 baths, living room, carport, and kitchen. Just an ordinary house. However when I use various formula's I end up with 3 ea 30 Amp Circuit breakers and 2 each 20 Amp.

Break down is as follows: 30A breaker for AC(2)/Water Heaters(2), 30A for additional AC(1)/WH(2) Kitchen Plugs, 30A WH(1)/External Lighting, 20A for Plugs and Int Lighting, and a final 20A for more Plugs and Int Lighting.

I found the 24 pages of Electrical Info on Thaivisa after I posted my questions above, and read all pages. I also downloaded all of 'Çrossies' data - Thanks Crossy and Elkangorito -. I feel a lot more comfortable now as to what my real needs will be.

The number of breakers and breaker AMP as listed above may be more than I need? Based on the above I would need 2.5mm and 1.5mm cabling. I like the idea of having an extra large Circuit Panel Box.

As I stated above, thanks for all the info from everyone. It is very much appreciated. I am always open for any suggestions anyone want to provide.

WARNING - I WILL NEVER attempt to do any electrical work myself. BUT I do need to figure out what my practical requirements would be before I hire an electrician.

Forgot to add: My 'stupid theory' was that a 100 Amp meter was necessary because I have 3 - 30Amp and 2 - 20Amp circuit breakers? In other words - a 'meter size' is based on number of circuit breakers and overall Amperage?

Oops! From another Q I just read on the board. My house size will be approximately 122 sq meters. There will also be 2 water pumps - don't no the size right now - think something like 3,000 watts(?).

Edited February 10, 2007 by grumpy_old_retired

[elkangorito]

I did grumpy's max demand calculation based on 3 bedrooms, and 2 bathrooms with the normal living room, a kitchen, carport and porch (plus whatever other rooms he mentioned in his drawing). I allowed for 48 double power outlets & one 15 Amp outlet, 17 lighting points & two 3.6kW instantaneous hot water heaters. Each light was assumed to be less than 60 Watts (incandescent) or 40 Watts (fluorescent). The total calculated maximum demand came out to be about 50 Amps, according to AS/NZ 3000:2000.

This demand does not warrant the installation of 3 phase.

If two single phase 220v 3kW motors are to be added (assumed power factor of 0.8), then the new maximum demand would be about 76 Amps, which is bordering on warranting the installation of 3 phase.

[chownah]

Grumpy Old Retired,

You can significantly reduce your power requirement by using gas water heaters instead of electric....also this will eliminate the dimming of your lights everytime someone showers which is really really common in Thailand in houses. In some places the service voltage coming to a house will drop at certain times of the day which makes the lights really susceptabel to dimming when water heaters or air cons are running. Also, I don't remember where you will be building but if its in the north then remember that it gets chilly here in the winter and a gas water heater will give you a hot shower in conditions when most electric heaters won't.

Chownah

[elkangorito]

In a PM Grumpy sent me, he asked the following questions (in blue);

1. How many Circuit breakers and Amperage would I need?

2. Can you explain, briefly, what 3 phase is?

In answer to your questions above, you would need to share your lights over 2 circuits so therefore you would need 2 x 16 Amp circuit breakers for this.

I recommend putting no more than 4 GPO's (power outlets) on each power circuit. Since there have been 24 GPO's allowed for in the above estimate, you would need 6 power circiuts ie 6 x 20 Amp circuit breakers. You will also need an extra 1 x 20 Amp circuit breaker for the 15 Amp GPO.

The 2 instantaneous hot water heaters will each need to be put on their own special circuits. I recommend that you use a 30 milliamp/20 millisecond Earth Leakage Circuit Breaker (aka ELCB, RCD, GFI etc). The current rating of each ELCB should be 20 Amps. This ELCB should NOT be adjustable in any way.

All of your lighting circuit cable should be no less than 1.5 millimetres squared copper cable rated at 600 to 1000 volts.

All of your power circuit & heater circuit cable should be no less than 2.5 millimetres squared copper cable rated at 600 to 1000 volts.

All GPO's should be 3 pin (earthed). The entire installation should be properly earthed & an MEN link should be installed.

All circuit breakers should have a minimum fault current interrupt capacity of 6000 Amps (6kA).

I didn't, at the time, explain what 3 phase is, so here goes;

Excluding network distribution detail & any discussion about 'balanced' loads, electricity is generated as 3 individual voltages that are 120 electrical degrees apart. This is then distributed as 3 individual 'active' conductors together with the Neutral, which is the cable that provides the 'return' current path back to the generator, to complete the electrical circuit.

In Thailand, the voltage of any one phase compared to neutral is 220 volts. The voltage of any phase compared to another phase is 1.73 times 220 volts (380 volts).

[Naam]

question for "elkangorito":

i have two 3-phase fans in my home (an attic fan and a whole-house fan). the fans were ordered by mistake of my builder as i requested single phase to run them on timers and/or thermostats. now i am stuck to manual switching or do you have any idea to solve the problem? each fan is ½HP only.

what puzzles me is that in Thailand 3-phase motors exist which do not need a neutral. never experienced this before. any explanation?

[Pink Mist]

question for "elkangorito":

i have two 3-phase fans in my home (an attic fan and a whole-house fan). the fans were ordered by mistake of my builder as i requested single phase to run them on timers and/or thermostats. now i am stuck to manual switching or do you have any idea to solve the problem? each fan is ½HP only.

what puzzles me is that in Thailand 3-phase motors exist which do not need a neutral. never experienced this before. any explanation?

delta connection only needs 3 phase, ok for small starting currents, though these days VF drives and soft starters have taking over so starting currents arnt an issue.

[Pink Mist]

sorry I missed the original question

ok this is how you do it, you get an electrician to fit a timer which drives a 3 phase contactor, the contactor controls the motor, so simple.

[elkangorito]

question for "elkangorito":

i have two 3-phase fans in my home (an attic fan and a whole-house fan). the fans were ordered by mistake of my builder as i requested single phase to run them on timers and/or thermostats. now i am stuck to manual switching or do you have any idea to solve the problem? each fan is ½HP only.

what puzzles me is that in Thailand 3-phase motors exist which do not need a neutral. never experienced this before. any explanation?

As bronco said, most 3 phase motors are Delta connected. But even it were Star connected, it still wouldn't require a neutral. The reason is that a 3 phase motor is considered to be a 'balanced' load & so no 'out-of-balance' current is produced.

Also as bronco said, use a contactor & a timer to control your fans. The contactor needs to be 'AC3' rated to accommodate your load. Generally, the smallest size contactor (about 4kW AC3) will more than fulfil your requirements. I would use Telemecanique, Cutler Hammer, ABB or any from one of the major suppliers/manufacturers.

[Naam]

sorry I missed the original question

ok this is how you do it, you get an electrician to fit a timer which drives a 3 phase contactor, the contactor controls the motor, so simple.

the problem is a bit more complicated as i use a frequency converter for the attic/roof fan to select RPMs which do not cause vibrations throughout the roof steel structure. can't run it higher than 42Hz without vibrations. the freaking electronic converter cost ~14.000 Baht (more than the fan!) but can only be triggered manually.

as it looks i have to live with my problems