convert VD to $$

[-marty]

My customer wants a service say 600 feet long. I figured if he's drawing 26 amps I should use 1/0 al for approx 3% lose or for 52 amps I should use 4/0 al for approx 3% lose. The house is on a genset now and they are very conservative with there usage. Of course when you have silent electricity you tend to use more.

What should I use for amps in my vd calcs ?
(genset is 6.5k 120 volts, not 240v )
(house will be rewired for 240v)

Say I figure 26 amps (off the cuff) so I use 1/0, then how do I figure how much extra it will cost him to add more load?

sorry I couldn't word this better and thanks!!

 

[bphgravity]

Re: convert VD to $$

Voltage Drop is a relationship between distance and load on a conductor. Determining the loss is dollars is not easily calculated. Voltage drop effects efficency of equipment, life of equipment, life of the wiring sytem, temperature at terminations, and a host of other issues. Base the voltage drop conductor size off of the sized service you will be installing and not the actual load. For example, if you are installing a 150-amp service, use that value for the VD calculation and not the actual load which may be less. The idea is to ensure that you can actually get 150-amp out of that conductor and service without significant VD.

 

[charlie b]

Re: convert VD to $$

I agree with Bryan. You?re not going to be able to justify a 4/0 versus a 1/0 on the basis of dollars saved because of lower power losses. For the situation you described, you have to go where the code will not take you; you have to look at successful performance of the system. If you size the conductor for less than the generator?s rated 52 amps, and if the customer later wants to add more than the present 26 amps, then the customer?s problem will not be the cost of power losses. The customer?s problem will be that some of the load might not function properly (i.e., because of low voltage). Ask the customer for an opinion of what that would cost, and I think they?ll agree to pay for the larger cable.

 

[-marty]

Re: convert VD to $$

Bryan and Charlie,

Thanx for your time. I understand what you are saying. My customer only understand dollars up front.