Talk:Electricity Upgrade

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Revision as of 12:38, 7 October 2008 by Jstockford (talk | contribs)
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based on on-site discussion and email suggestions.

initial document written tuesday, 20081007, 10 AM or so.

please add comments, do not delete any text you have not yourself written.


currently the plan for electrical upgrade at 83c is as follows.

schedule: plan to work thursday and friday, hopefully AM, hope to finish friday late afternoon, but finishing never happens as planned.

materials: EMT pipe and metal junction boxes.

  • remove subpanel cover and discover the reality inside, mainly how studs and firebreaks are located.
  • somehow, hopefully above the subpanel, punch a hole and install a four-square junction box and put an extension on it, only for wires, with a blank cover.
  • run pipe from the extension up the wall and across the edge of the ceiling toward the fishbowl shop, punch through the wall and end the pipe run with another junction box where the wall meets the ceiling ("initial j-box").
There's a mini-wall sticking out on the inside of the fishbowl wall, which I believe is only there to cover a vertical pipe but has no other structural function. The diagram on the main page shows a hole in the fishbowl wall to the outside of this mini-wall, and a hole through it. I believe the ceiling pipe could just as easily run to the inside of the mini-wall, removing the need to punch through it. Rachel 11:47, 7 October 2008 (PDT)
bending pipe to aim for a hole is probably more work than punching a new hole. thank you for the info, i'll check it out on site and, if no objections, do what seems easy and good. --Jstockford 12:11, 7 October 2008 (PDT)
  • from the j-box in the workshop, run a length of pipe around the room at the ceiling-wall corner with j-boxes on each of three walls. also run pipe from the initial j-box to the light in the center of the ceiling.
  • from each of the ceiling-wall j-boxes, drop a piece of pipe down to another j-box 44 inches on center above the floor.
  • remove the current ceiling light fixture, inspect the box in the ceiling, add appropriate extender to accept pipe from the initial j-box, connect the pipe from the initial j-box to the new ceiling light extension. run a length of pipe either
    • from ceiling extender across ceiling down some wall for a j-box for a switch 48 inches above the floor

or

    • from the initial j-box down the wall to a j-box for a switch 48 inches....
MILESTONE: pipe work is now complete, ready for wires
  • in subpanel, add new breakers as necessary and run wires for the following circuits:
    • four circuits for receptacles in workshop
    • one circuit (hopefully a branch of that which powers the kitchen ceiling light) for the workroom ceiling light.
NOTE: it is always a good idea to ensure circuits that power receptacles do not also power lights because using receptacles is the most likely means of tripping circuit breakers: if the breaker trips, it's nice that the lights are still on, a matter of safety.
  • pull wires from sub-panel to workroom terminal j-boxes (the ones 44 inches up) and the extension for the ceiling light and switch leg.
  • wire devices as follows:
    • connect and install ceiling light and its switch
    • install double duplexes in each terminal j-box, separate each receptacle, wire each to a different circuit, color each receptacle to reveal its circuit.
    • put coverplates on all j-boxes (probably an industrial tough EMT-like metal cover, in which case to which the devices are attached).
MILESTONE: workroom electrical upgrade is now done


NOT ADDRESSED ABOVE

THE LOFT: how to improve the electricity for the upstairs ("loft"?).

  • how to get pipe up there: across ceiling and wall surfaces is best, minimize punching holes and trying to fish within walls.
  • there may be an accessible branch point (at the j-box in the toilet room or in the subpanel itself) where it's possible to break the connection to the upstairs #14 receptacles, presenting the job of getting wires from the subpanel to that point.
  • the loft has two circuits, #14 and #15. what power is required? issues are heavy loads and noisy loads. motors are both heavy (draw a lot of amps) and noisy (spikes and lows as motor turns off and on); heaters (hair dryers, hot plates...) are only heavy; some electronic devices can be noisy (return high-frequency waveforms into the line, often on the neutral return).

SO WHAT IS THE EXPECTED USE IN THE LOFT?

The loft will have two large electric users -- soldering irons, and rackmount computers. I would expect a max of 5 200W soldering irons in use (call it 10 Amps), and a max of 10 machines at 200w each, or about 17 A. (Some of the machines will draw more but most will draw less.) We should verify the specs on the large UPS that's upstairs. There will also be misc users like lab gear, maybe another 5A to be generous. Adi 11:45, 7 October 2008 (PDT)
NOTE: solder irons for electronics are 25W or 35W, so 5 of them on at once is about 2 A (rounded up). Mitch Altman 11:55, 7 October 2008 (PDT)
this is my experience also. there are soldering guns and irons of 100W, but for electronic work they have only occasional use. --Jstockford 12:11, 7 October 2008 (PDT)
if soldering is done upstairs, good chance people will be screwing around with electronic circuits, which presents the chance of inadvertent short circuits. probably good for electronicists to plug into fused receptacles, which could be little gizmos that plug into wall receptacles and present fused receptacles on the working side. i'd guess 5A would be plenty for most projects (including scopes, meters, soldering stations, circuits under test...). --Jstockford 12:11, 7 October 2008 (PDT)
a dedicated 20A circuit is needed for the computer equipment. most 1U boxes suck 1A. good to know
  • the specs for the rack itself (how many units), four-post or two-post, shelves etc available?

and for

    • each machine (1U or 2U or what, and amperage for each).

so how to run the dedicated circuit? --Jstockford 12:28, 7 October 2008 (PDT)


OTHER: there are other possible useful projects:

  • shannon clark in email raised a good point: task lighting for workstations. this applies not only to the electronic workstations in the loft but all workstations (in the fishbowl, chemistry, darkroom, computer stations...). a NOTE above suggests not letting a circuit power both lights and receptacles. as long as some light is lit when a breaker trips, safety concerns are okay. more receptacles can come from power strips or from adapters that plug into a duplex and present six receptacles. --Jstockford 12:37, 7 October 2008 (PDT)
  • isolated AC 110: get an isolation (1:1) transformer and put a receptacle on its secondary or get two identical step(down | up) transformers, hook one primary to AC, connect secondaries, hook a receptacle to the other primary winding.
BENEFIT: isolated ground, reduced problems with noise and electrical shock hazard.
  • UPS: probably good to have transformer isolation, but at any rate, make a circuit that charges a battery that can kick in to power an AC 110 emergency circuit, features can include some electronic notification of switchover and a warning of battery-too-low condition, even logging. more Amperage (i.e. more Watts) requires more money, lots more. --Jstockford 12:11, 7 October 2008 (PDT)
  • complementary 12 VDC or other DC power system. could use uncomplicated battery backup to provide emergency power (lights, laptops). (there are 24VDC, 48VDC... (i like +12VDC with -12VDC dual tracking, but that's probably an audio-only approach).
  • it might be nice to put some kind of spike/noise suppression on certain circuits, both to protect their devices from the clatter of other circuits as well as to prevent their clatter from bleeding out to other circuits. --Jstockford 12:28, 7 October 2008 (PDT)