One Wire Size Up

Look at the other side of the coin,we will consume more copper,a very valuable resource.

Something your typical home buyer wouldn't even consider. But the pay-back is forever.

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I think for homes it is not economical. However for industrial customers with 24 hr operations it can be a money saver.

Saving money is not all. even if you have a million dollar if you are thirsty you can't drink money,you need water. That's why they say save water,electricity,food,resources (metals),environment etc. We should keep resources for our future generations who should not blame us.

Up size your wiring to reduce copper losses!!??

How about lifting your(American) minimum utility supply voltage from 110 to 220VAC? That'll quarter your current copper losses.

Good idea but what percentage of total copper is used in wiring domestic/commercial and industrial lighting and small power?. Is it more than the copper used in motive power wiring in industries?.

Common sense. Simple engineering calculations that should be done as a matter of course after checking minimum conductor sizing dictated by local codes.

The payback of upsizing conductors is hugely dependent on the input variables. For example, some plants here in BC, Canada, can purchase power for about 4 cents per kWhr. This very low power cost does not play well in the calculations for upsizing conductors. Also, predicting motor loading and duration of loading can be a bit of a guessing game, unless you have similar plants where you can gather data from.

Where I end up with my jaw on the floor is from some who suggest that I am a bad person by not considering using minimum resources (copper), and instead waste power by using minimally sized conductors. Save the copper for my kids to use instead. Hunh? Last I checked, copper was recyclable. The extra energy the tree huggers are implying I should use today isn't quite so recyclable.

The poster who suggests that North America would be better off by going to 220V from 120VAC is spot on. I guess we got caught in this one by history, where a not-such-a-good-idea of using 120 VAC simply evolved without any long term thinkers helping to guide it. Not sure this could be easily changed without the flat earth types coming unglued.

Industrially, higher voltages have been "sort of" tried here in BC, Canada, where there are lots of plants at 480V 3-phase and lots of others at 575V 3-phase. (Not sure if this happens in the US or overseas, although I would suggest the lower voltage 415V 3-phase power used outside of North America isn't as efficient.) Going to 575V when building a greenfield plant is easy, assuming you can buy the power at some higher voltage and are installing your own substation. However, for the longest time the variable frequency drives available for 575V weren't that good, and that soured lots of people against the higher voltage.

Jon.

Copper is recyclable but what percentage is actually recycled but end up in landfills. Not only copper but glass,plastics,metals,electronics,food too end up in landfills.Will the authorities take responsiblity or they think of how to win the next election.

Actually, I do not agree. The assumption of the article is that all the differential heat will be ejected into the occupied air and that that air will always need to be cooled. Even if that were the case, air conditioning units don't cool on a one-to-one kW basis. Even a unit with a 12 SEER rating (or a COP rating of 3.5), we are looking at 7 - 10 years payback for the continuous lighting load of 15A (which would probably trip the 15A breaker at some point). Much of the wiring in a residential home is run through the shell and most of that gets dissipated to the outside. Have you ever felt an interior wall to be warm to the touch because of wiring? I have not. If we assume that even 1/4 of this heat dissipates to the occupied space and has to be cooled, your payback is now into the 28 - 40 year range. If you only include summer as needing cooling (assuming you have an AC unit), you are now well over 100 years for the payback.

Looking at industrial settings, often times the conduits are buried. The heat differential becomes a moot point and there is no payback. Again, many times heating would be required in the winter time and heat gain is a non-starter. Save your money and invest it into high eff. motors, HVAC units, lighting, and better insulated building envelops. A much better return on your money.

And with a name like "Copper Development Association" I guess I shouldn't be surprised that they want us to up-size.

I agree with the premise but for entirely different reasons. I design power systems for pleasure craft. Operational cost is not the primary consideration but reliability is. Going one size larger we get slightly more voltage at end of line and less voltage drop (often referred to as copper losses) to distinguish them from other losses. In addition much of the copper wiring goes into low voltage circuits where a 2.4 volt loss is 10% in a 24V circuit. The standards define 10% as maximum permissible loss and critical circuits must not drop more than 3%. By upping wire size we avoid exceeding mandated parameters. Equipment works better and motors run cooler which equates to longer service life. There is nothing worse than needing some piece of equipment from half way around the world and having to deal with suspicious customs people 30% tariffs and intolerable delays in clearing customs.

So yes I agree and always upsize when possible. The exception being 4/0 cable because one size larger often pose physical constraints we can't cirumvent.

I would submit to you that you are actually not up-sizing above code, you are up-sizing because you need to meet mandated requirements and rightly so. The OP is talking about up-sizing above the (US) NEC code, i.e., where voltage drop is not the issue. In fact, I believe the code requires up-sizing to account for extra long runs to reduce the voltage drop. The article the OP refers to talks about up-sizing beyond any code requirement, which IMO is a waste of money and resources.

Not quite. I am in fact over sizing relative to what the standards require. Much of the marine standards are derived directly from NEC and NFPA.

It is common to use a 15 amp fuise or breaker on 120V AC branch circuits.The tables I use allow #16 AWG for 100 feet to produce 5.2% voltage drop yet the common practice is to use #14 Ga

I could go to 300 feet before I reached the limit with a 9.8% voltage drop.

Similarly on the DC side I aim for a 1% loss to sub panels in order that end of line voltage losses stay well within limits. In any motor driven vessel or vehicle vibration and chafe are significant wear factors. Going with larger sizes improves this resistance to mechanical wear rather than detracting from it. Yes it is true that wire cost are a bit higher, but it is still not a very significant part of the total cost, and the improvements in reliability is noted.

Very Simple Basics!

When the wire size is increased, the ohmic resistance/impedence of the circuit decreases. This leads to increased maximum voltage at the load terminals thereby increasing the current. This will consume more wattage. The 15 amp lighting load, as per the example 2 of the LINK consume more power. So from where does the saving come?.

With regard to higher voltages like 230VAC, it could be done by supplying each US/Canadian house with 3 phases of "phase to phase" 230VAC, phase to neutral for 120VAC for all older house units that need 120.....

The cost would be of laying extra cables from substation to the houses.....probably costing far miore than any savings....

In countries where the neutral is needed for single phase devices, simply increasing the size of the neutral to around 3 x the cross section of one of the phases might save some losses, but whether the savings would bring a financial "win", I am at a "loss" to answer!!

Merry Christmas and a Happy New Year.

Most homes in America today have 230v available. In the past I have wired in circuits for 230v appliances. These included heaters, air conditioners and clothes dryers and hot water tanks.

When I first got my house it had a 110v light circuit. It was enough to run a 230v water heater if I took a bath once a day. My range burners would work on medium so you could cook dinner if you were patient or use a 110v coffee pot or hot plate. Another time I was installing a water heater in a cabin and there was only 110 available so I did what I had to do.

One time at a neighbors house I had to repurpose a baseboard heater circuit for an electric hot water tank. The gas rates went up to where it wasn't economically feasible replace the gas tank with another one and since they had a gas furnace they didn't need the baseboard heaters anymore.

Where you really run into voltage drop problems is in low voltage low impedience circuits. I discovered that a few extra feet of wire on one channel of a stereo could throw the balance way off so now I always make both channels equal length and tie up the extra. My neighbor uses Monster Cable on a 25WPC amplifier which is almost overkill though.

I dare anybody to get an electrician to upsize wire if said electrician doesn't feel the need. I moved my meter from my house to my detached garage. I had to twist the electrician's arm to get him to put 2 AWG copper instead of aluminum so I wouldn't see as much of a drop at the house.

When I moved the meter, I had the service put under ground. At least the utility put 4/0 from the road to my meter. Of course they didn't change anything along the road to the transformer. Oh well, their loss!

If the contractor had already submitted a bid based on the lower cost of course he will not agree to higher priced material. That come out of his pocket.

This is a design detail that has to be stipulated at the outset before a price is agreed on.

I for one have always over sized on wire whenever possible. It seems like no matter how well you design an electrical system there comes a time when its not big enough or you wish the circuits would have been one size larger.

Personally I do not wire anything in a house to less than a 20 amp circuit for any single room. As far as I am concerned 15 amp circuits are for single use dedicated items like the furnace controls, the washing machine, garage door openers and such.

I originally wired my shop with 12 gage wire and 20 amp circuits but now when I go to put in the new walls and insulation I am very tempted to step it up to 10 gage wire and 30 amp breakers for most of the outlets. I have too many high powered tools that just cant work together if they are trying to share a single 20 amp line.

I can't imagine trying to work with 10 gauge wire in a box to a outlet. For your situation I would recommend a small distribution box for the power tools fed by a nice big wire. 12 gauge is difficult enough to get on an outlet, 10 is really stiff. The lights and other stuff can be fed by another box.

Apparently I must have unusually strong hands! I don't find 10 ga the least bit difficult to work with in confined box spaces.

Thanks for sharing.

...you "pay" for power by the Kilo-Watt-Hours -- not by the Volts or Amps -- so anything that reduces "loss" is a savings!

...when having A/C installed in our 28-year old house, I specifically asked that "next size larger" wiring be used between it (compressor) and the service box, which (ironically) didn't cost me a cent more. The electrician simply said "OK."