Hi all, here is a little application problem which I am hoping some of you may be able to help with. My Electrical knowledge is far from comprehensive so feel free to keep it simple!!!

Unfortunately, down here in Belize, (110V single phase) sound Electrical know-how is difficult to find. As a result with any help you may be able to give, I can try and grasp the full extent of the situation I have before me.

My “problem” is based around needing to supply 2 large Houses (under construction) with mains power. The nearest house is 600' from a dedicated 25kVA transformer - the furthest 900'. In between the two is a Utility Building housing a Laundry room - 1 Washer and 1 Gas/Electric Dryer. The two houses are split into independent self contained upper and lower level units. Without Aircon, electric cooking, Hot water heating, or any electric motors other than the odd power tool now and again; the max peak load I would estimate for the whole site is unlikely to be higher than 50A.

I am currently in the process of sizing the Cable required to bring the Mains electricity to the site. As you might guess, my main concern is that of Voltage drop along that length of line and disparities in the Voltage between the two houses. The Electric company says it can boost my voltage supply up to 130V and supply a up to 125A from my transformer.

My issues are:

1) On a 110V supply, at what voltage drop level would I start to noticeably experience appliance problems, lights dimming, etc. I believe 2% is generally used but is that practical?/reasonable?/necessary?

2) With the advice of the Electric company (whose advice is not consistently good!) I am anticipating using copper 00 cable which by my calcs using the online calculators leads to a VD of 8.7V at the furthest house equating to 7.3%

3) The Electric company only considers the one length 900' and NOT the return so say the VD will be about “4V” and therefore fine!

4) I originally wanted to take the supply to the centrally located Utility Building and supply each house from there equalizing the Voltage somewhat but this could now add to the problem by adding a longer line plus the cost of 00 Cable is high here in such quantities. As an addition, can I step up the Voltage in a line that has already been stepped down?

5) I guess what I would like to know is how sensitive to supply voltages are Lights/Fans/Fridges? My current thought, open to amendment is to run a 00 spine through the site, branching off from it to supply the two apartments in House 1, then the Utility Building and then the apartments in House 2. I realise that in doing so I will have to accept that House 1 and 2 will have different supply Voltages, which is fine as long as is functionally negligible

6) If the above is feasible what size cable can I branch off the 00 spine and which would be the best way to branch it?

7) Does the Neutral Line HAVE to be the same size as the Hots? If not how small can I reasonably go?

I realize I am probably not using the correct terminology in much of this so please excuse my ignorance. I am happy for anyone to point out the errors of my thinking or approach and very grateful to receive any constructive suggestions from you electrical bods!

Thank you