[Elecraft] KPA500 AC power

[Edward R Cole]

Make sure the 120v line/outlet is not getting warm.  Measure ac 
voltage with amp off and then in keydown transmit to check voltage drop.

I don't have a KPA500 or KPA1500 but did have a 8877 with 
4kV  PS.  It ran at 750ma  which is 3000w dc load.  That converts to 
12.5A at 240v  if PS is 100% efficient.  At 120v that would run 25A 
which exceeds rating or No. 12 house wiring.  I  now have a 1200w 
sspa that draws 50v-50A  (2500w dc).

I installed my own 240v using 8-4 wiring bought at Home Depot.  I get 
about 2vac drop when keydown at 1500w RF.  I installed a small 
breaker box in the shack with one dual 20A breaker for 240v and split 
out two 120v 20A ckts which run my 12v-50A station PS and a 26v MOT 
repeater PS for my 220-MHz 150w PA.  I also have a 1000w 50-MHz sspa 
powered by 50v-50A switching PS (2500w dc) that uses 240vac.  Only 
run one QRO amp at a time.

Running the 8-4 wire from my main load center down thru crawl space 
under the main floor then back up thru spare bedroom (shack) floor; 
about 35-foot run.  I drilled small holes in floor joists to tie off 
the cable using wire ties.  Crawl space is 4-foot high.  Obviously if 
your house is on concrete slab you would need and 
alternative.  Suggest running outside on house wall with conduit 
(which can be pvc if cable is sheathed).

We have very lax building codes up here so home self-construction is 
common.  Have a licensed electrician do the work if codes require 
(for insurance coverage).

73, Ed - KL7UW
   http://www.kl7uw.com
Dubus-NA Business mail:
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