One size up

[bob]

Interesting article on savings by increasing conductor size http://www.copper.org/applications/electrical/energy/onesizeup.html


I am also searching for a post that I think Iwire posted for an on line motor calculator. I can not find it.

 

[norcal]

How would you work around 250.122(B)?

Here is a copy & paste of the text.

(B) Increased in Size. Where ungrounded conductors are
increased in size, equipment grounding conductors, where
installed, shall be increased in size proportionately according
to the circular mil area of the ungrounded conductors.

If the conduit is used for the grounding conductor there is no issue, but if there is.......

 

[Hv&Lv]

How would you work around 250.122(B)?

Here is a copy & paste of the text.

(B) Increased in Size. Where ungrounded conductors are
increased in size, equipment grounding conductors, where
installed, shall be increased in size proportionately according
to the circular mil area of the ungrounded conductors.

If the conduit is used for the grounding conductor there is no issue, but if there is.......

Doesn't this cover it?
"All three examples include a separate full-size grounding conductor, following current recommended practice, and use THHN copper conductors."

 

[Jraef]

Given that the source is the copper industry, I'm not a bit surprised. Everyone is trying to ride the "emery savings" train now.

 

[kwired]

Lets throw more variables into the calculation before we determine how much is saved.

How much less heat is required from the heating system when we have excess heat from all the conductors inside a building?

How much more energy is needed for cooling the building becauase of the heat gained by these conductors?

What is the net for the year after considering both of these factors? Now throw that into the calculation to determine whether or not is justifies using a larger conductor.

Remember it is also the copper industry that is suggesting you use more copper:happyyes: not to say it does not deserve consideration.

 

[bob]

For residential customers is too long a payoff. However for an industrial customer with a 24 hr operation it can be a money saver in a short period.

 

[broadgage]

Yes, most residential branch circuits are either lightly loaded or heavily loaded for relatively few hours a year.
Use of larger conductors than code mimimum will save energy in such cases, but very little in comparison to the extra cost of a larger wire.
In view of the rising cost of electricity, it might be worth upsizing wire sizes for residential long hour loads such as water heaters or A/C units. Unlikely to be worth it for lighting or outlet branch circuits.
I suspect that most residential 20 amp branch circuits have an average load of less than 2 amps.

For large loads that run throughout the work day, or even 24/7, in a business then do the math ! upsizing is often worthwhile on energy saving grounds.
Consider a feeder for a 24/7 100KW load with a loss of 2%, that is a waste of 17,000 KWH a year or perhaps $1,000 a year.
A larger cable that halved this loss would be a wise investment if it cost only a few thousand $.