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3 phase

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kwame

Member
Hi
i am very conversant with single phase house wiring but, in recent times use of three phase in the wiring of homes is on the rise.
Folks, can someone provide a simple guide/circuit for 3 phase house wiring?
Missing you lots!

Kwame
 
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johansen

Member
i've never heard of 3 phase being available for residential homes.

120/208 might be on the rise if an appartment block were run off 120/208 three phase but only 2 phases would be run to each home.

the connections are more or less the same as 120/240.

what exactly are you looking for?
 

crutschow

Well-Known Member
Most Helpful Member
A 3 phase delta connection requires 3 hot wires plus a safety ground wire or 4 wires total. A 3 phase wye connection requires an additional neutral wire. 3 phase is normally only used for high power industrial requirements (large motors, large electric furnaces, etc.). There's typically no reason to run it to a residential house.
 
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ChrisP58

Well-Known Member
I saw 3 phase power once in a large house for the airconditioning.

As far as the single pole distribution in the house, there is no difference. Two pole loads expecting 240 VAC, such as a clothes dryer, can be a problem as the phase to phase voltage is only 208VAC.
 

KeepItSimpleStupid

Well-Known Member
Most Helpful Member
For people that have NEVER heard of 3-phase residential, see page 3 of thie PDF for a Florida Utility: http://www.electro-tech-online.com/custompdfs/2012/06/Ess3SvcProvision.pdf

It CAN be had in some locations.
D. Residential Service (under 600v)
A single, one phase, 120/240 volt, three wire overhead service drop per lot is the standard service
offered by FPL to residential customers. Excluding any extension charges that might apply
(section III.C.2) this service is offered at no charge to FPL's designated point of delivery. Three
phase service may be available
but only under special circumstances and CIAC charges might
apply.
 
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crutschow

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i could pay 3 times the monthly flat rate and a few grand for them to come out and install two more transformers if i really needed it as well :)
Actually they just need to replace the single-phase transformer with a 3-phase transformer. ;)
 

ronsimpson

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Here in cites the the 3-phase answer is a flat NO. It is not available and the wires are under ground and can not be changed.

I have 3-phase 1000 feet away. I would need to replace 3 poles, add more overhead wires, new transformer, new power meter.
 

Reloadron

Well-Known Member
Most Helpful Member
Hi
i am very conversant with single phase house wiring but, in recent times use of three phase in the wiring of homes is on the rise.
Folks, can someone provide a simple guide/circuit for 3 phase house wiring?
Missing you lots!

Kwame
You don't mention where this is happening?

Here in the US 240 VAC 60 HZ single split phase is the normal power for a residence (individual home). This includes 200 Amp service. Appliances like pumps, electric ranges and clothes driers take advantage of the 240 volt service. The only use I could see for three phase power to a residence is if someone wanted to run a large motor (exceeding 10 HP). Therefore as Carl points out, I would see no reason for 3 phase power in a residential power distribution system.

However, if there was a need I can see using what is called a High Leg Delta (a few other names are used) which is configured like this.

Just My Take
Ron
 

dr pepper

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I've seen 3 phase in homes before, one was the farm where I used to live, the supply, fuses and meter where in the house for all the farm machinery, and perhaps a more apt application was a mates house where he had electric economy 7 storage heaters, these were fed from 240v single phase however the load for all the heaters were spread accross all 3 phases (some on each phase).

In the uk there are fairly strict rules for domestic wiring, you really ought to check your covered to do such work, house insurance can be invalid if works isnt carried out by someone with the correct certificates.

Unless you have very heavy loads like multiple storage heaters or industrial equpiment there isnt really a serious need for 3 phase in a domestic situation, in fact its more of a risk than an asset.

If you want to power a small machine like a mill/drill or small industrial machine like a small pump then you can get variable speed drives that convert single phase into 3 phase, the output is 3 x 220v rather than the usual 3 x 415v, this normally isnt a problem as most small motors can be reconfigured from 'star' connected to 'delta' connected, which converts from 415v to 220v, such drives only go up to about 2kw (1.5hp or so).
 
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KeepItSimpleStupid

Well-Known Member
Most Helpful Member
The guys that want three phase are the guys that want/have a machine shop. I could also see a McMansion with a few three phase air conditioners as well. Mr. Fixit, the handyman, would probably have issues.
 

unclejed613

Well-Known Member
Most Helpful Member
or if you really need 3-phase, it's probably cheaper to get a rotary inverter (a single phase motor and a 3 phase alternator on a common shaft) and have it installed, than it would be to have 3 phase run to the house, and also have the wiring of the house re-done. the 3-phase power would then be available when you need it without the gigantic monthly charges on your electric bill.

http://phoenixphaseconverters.com/
 
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