Acceptable percentage of voltage drop

in article snipped-for-privacy@uni-berlin.de, Bob Peterson at snipped-for-privacy@insightbb.com wrote on 11/22/04 11:36 PM:

I agree, especially since I'm a rank amateur. However, I'm having trouble finding a local supplier for UF cable of that size.

message

conduit or

crazy. UF cable

having trouble

Like bob said, you have a diverse load... all of it will not be running at one time..Id dump the instantaneous electric water heater though for sure..or go to one with a 20 amp heater element and tank,..or propane.

Phil Scott

is in East Texas.

Nice country...I had a place near Livingston for a while.

substantial

period, we'll

They do have tankless propane heaters that use a 110v starter element. They're just a pain to install because they have to be vented.

The reason I want to go tankless is because of #1 space and #2 I don't want to heat water when I'm not there.

only

just

big

starter element.

vented.

#2 I don't want

Turn the thing down to 60 or 70 degrees (so it doesnt freeze) when you are not there and wrap the tank in insulation.

You can get a 10 galon water heater.. and put in it in a shed attached to the cabin. if its electric you can pack the shed with 6" of insulation. it wont cost much on stand by that way.

For heat and ac you might want to consider a window heat pump... chinese made for 200 dollars or so... used occasionally it will last forever.

Phil Scott

if you are a rank amateur you are better off letting someone who knows what they are doing take care of it.

Having said that, any electrical supply house can special order you whatever you need.

Put it on a light switcj that you turn off when you leave. It will heat back up in a few hours after you trun it back on.

just hang the thing on the outside of building and venting is easy

in article 29Bod.139507$R05.119239@attbi_s53, William at wac@_nospam_gene-o-tech.com wrote on 11/23/04 12:54 AM:

Can they be mounted outside? If so, that would solve all my problems.

Randell Tarin wrote in news:BDC7F539.E15B%the snipped-for-privacy@sbcglobal.net:

Why not just set a ground mount transformer near the cabin and have the Elect Co run underground service to it from the pole? Many subdivisions use this principle now. Probably be about the same money either way, if not cheaper.

Yes. Undoubtedly.

I didn't bother to do the calculations but...

Have you considered simply up-sizing the conductors by one step? It would be (relatively) cheap insurance and certainly can't hurt. Certainly it would be cheaper to over-do it a bit in the beginning that to have to do it again later, possibly after having equipment damage caused by excessive drop.

Yes they can, unless it gets below about 20 or so deg. They have a thermostat that turns on a small electric heater in the heat exchanger on the better models so they will not freeze up at 32 or so. My buddy has one mounted out side in Oregon and it gets colder there than most places in Texas and it's running just fine... It gets -15 below zero here, so outside is out of the question here. I have to have a flue damper and remotely mount the thermostat that controls the heating block to the outside of the building, so a really cold blast of -15 air will not flash freeze the heat exchanger

It's WAY cheaper than the 7200 volt or higher rated wire used to run to the transformer.. lots of utilities charge LOTS of $$$ to run to the transformer They want $4500 to run to the transformer for my house from the poll ( about 350 feet)

William....

| It's WAY cheaper than the 7200 volt or higher rated wire used to run to the | transformer.. lots of utilities charge LOTS of $$$ to run to the | transformer They want $4500 to run to the transformer for my house from | the poll ( about 350 feet)

I'd just run 480 or 600 volts for that distance. Of course you might have to do some talking to get the utility to hand off at that voltage. And then there is still a transformer needed.

Not a cost effective idea either, as I found out the "hard way". For instance if he wants to have a 200 amp service to the cabin he needs to run a 75kva transformer. At those voltages I don't think that they will sell you only 2 lines, so he would need a 3 phase transformer just like I'm running now. So here are the problems, first the cost of the transformer is on the user ( bad enough) but the little part they don't tell you is that the transformer eats 600-800w just to turn it on! That's every second of every day you run it! I wanted to run 300 amps so I got a 112.5 kva to run at my house that little pig burns 1200w can you say ChaChing! That's why I'm going to let them charge me the $$$$ to run the high voltage to THEIR

William....

|> | It's WAY cheaper than the 7200 volt or higher rated wire used to run to | the |> | transformer.. lots of utilities charge LOTS of $$$ to run to the |> | transformer They want $4500 to run to the transformer for my house | from |> | the poll ( about 350 feet) |>

|> I'd just run 480 or 600 volts for that distance. Of course you might have |> to do some talking to get the utility to hand off at that voltage. And | then |> there is still a transformer needed. | | | Not a cost effective idea either, as I found out the "hard way". For | instance if he wants to have a 200 amp service to the cabin he needs to run | a 75kva transformer. At those voltages I don't think that they will sell | you only 2 lines, so he would need a 3 phase transformer just like I'm | running now. So here are the problems, first the cost of the transformer | is on the user ( bad enough) but the little part they don't tell you is that | the transformer eats 600-800w just to turn it on! That's every second of | every day you run it! I wanted to run 300 amps so I got a 112.5 kva to run | at my house that little pig burns 1200w can you say ChaChing! That's why | I'm going to let them charge me the $$$$ to run the high voltage to THEIR | 75kva transformer and then THEY can pay the $$$ to keep it warm ( not a big | deal to them as they pay like 1-2 cents per kw unlike the 8-11 cents I pay.

Utilities typically undersize transformers. For 200 amp service, you might get a 37.5 kVA transformer (at least if it's a pole mount). They figure you will not be pulling the 200 amps for such a long period of time that you would blow the transformer (there's a lot of margin to overload it for a few hours). Of course in Texas, there might not be as much margin given the ambient temperatures.

That's right THEY can YOU cant! So you have to run the 75kva for the 200 amp service or the 112.5kva for a 300 amp service. They figure that you will NEVER be pulling 200 amps at all. Lots of times you, nor your neighbors will be, and here they will put 5 or more homes one 50kva can! The only nice thing about their setup here is that the smallest 3phase pad mounted transformer they have is a 75kva so that's what they will give me for the home @ 208 volts and if I "need" the 480 volt stuff at the house I can run it off the feed to the shop.

| That's right THEY can YOU cant! So you have to run the 75kva for the 200 | amp service or the 112.5kva for a 300 amp service. They figure that you | will NEVER be pulling 200 amps at all. Lots of times you, nor your | neighbors will be, and here they will put 5 or more homes one 50kva can! | The only nice thing about their setup here is that the smallest 3phase pad | mounted transformer they have is a 75kva so that's what they will give me | for the home @ 208 volts and if I "need" the 480 volt stuff at the house I | can run it off the feed to the shop.

If you are using a pad mount 3-phase, then 75 kVA is probably the smallest you can get. I have seen smaller, but the major companies like CH and GE only make 75 and up. The savings for 45 or smaller would be tiny, anyway. The other issue is fault current. I can't find the impedance specs for GE but CH's 75 kVA padmount is 4%, meaning a fault current up to 5208.3 amps (and that's not figuring in other impedances which will lower it).