electrical short in barn?

o.k. hear I go. I no longer have electricty in my barn. A brief history that leads up to this post, I had my old barn re-decked, re-shingled last fall.
I started noticing about a month later my lights would dim and or go out completly then come back on again. Now the lights will not come on at all.(just outlets and light bulbs in barn no heavy equipt). When I test voltage at 220 switch coming into barn, 110v on each side is o.k. with all fuses off. but when I test voltage again with fuses turned on I get a drop of 90v on 1-side and 40 to 50v on the other, I've tried different fuses as far as 1-off, 1-on etc,etc. When I test a outlet for power I get 90v. Any ideals would be very helpful, thanks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

This is one of those situations that without being there hands on (well, insulated-glove hands on (c: ) it's near impossible to diagnose.
But, if you're measuring ~90v at the service input to the barn with "fuses on", and you're not blowing any fuses, I'd say you have a wiring problem *in* the service connections or *prior* to the service connections to the barn. Check back to the source all connections and wires.
Might be time to call an electrician...
Good luck,
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Daveh wrote:

Loose connection, construction activity damaged the feed to the barn, or nail penetrated the wiring.
Ed
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
| o.k. hear I go. I no longer have electricty in my barn. A brief history that | leads up to this post, I had my old barn re-decked, re-shingled last fall. | I started noticing about a month later my lights would dim and or go out | completly then come back on again. | Now the lights will not come on at all.(just outlets and light bulbs in barn | no heavy equipt). When I test voltage at 220 switch coming into barn, 110v | on each side is o.k. | with all fuses off. but when I test voltage again with fuses turned on I get | a drop of 90v on 1-side and 40 to 50v on the other, I've tried different | fuses as far as 1-off, 1-on etc,etc. When I test a outlet for power I get | 90v. | Any ideals would be very helpful, thanks.
There is a broken connection coming in. You are most likely reading a phantom voltage with a very high impedance digital voltmeter. When the wiring is extended longer (fuses on, as you say), the voltage drops due to the need for more charging current to feed that wiring. This phantom voltage is a small amount of capacitively coupled charge voltage due to one wire very close to another.
It is not a short. If it were a high current short, the fuses would blow. If it were a low current short (wire touching earth for example) then the voltage would not be pulled down so much to prevent lights from working.
Test voltages with very low power loads connected, such as an electric clock or a small gadget wall wart transformer. Or connect small wattage lights and see what you get for voltage readings across a range of load wattages. Repeat these measurements on both sides of the system where you were reading 90V and 40-50V respectively.
--
|---------------------------------------/----------------------------------|
| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.