Power Distribution Board Construction
Now that the heatsticks are done, we need a way to get power to them.
Ordinary residential wiring can only handle one heatstick per circuit. Even
if multiple circuits are available in your brewing room, they're probably
scattered throughout and relatively inaccessible. Switching heatsticks
on/off by unplugging them is also inconvenient, especially when your wort is
threatening to boil over and the plug you need to pull is on the other side
of the room.
This project takes a 240-volt 30-amp circuit (what your clothes dryer most
likely uses) and splits it out to four 120-volt 15-amp circuits that can
each power one heatstick (or other brewing equipment, like a swamp-cooler
pump feeding your wort chiller). Each circuit has a GFCI outlet on the end,
so that if something should go wrong with a heatstick, the outlet will trip
and you'll avoid a nasty surprise.
If you're building 2-kW heatsticks, you'll want to upgrade this project to
provide 20-amp outlets. A 240-volt 50-amp circuit (what an electric stove
most likely uses) will supply enough power. If you're putting in a new
circuit for use with your heatsticks, a 40-amp breaker (instead of 50) might
be a good idea. Upgraded parts are called out in the partlist where needed.
Note that the photos show a board being built for 1.5-kW heatsticks.
You'll need the following parts:
- two plastic 4-gang old work wiring boxes ("old work" means a box that
you'd stick through a hole in an existing wall for mounting; it has some
swing-out plastic tabs attached to screws that we'll remove for our use)
- four 120-volt 15-amp (for 1.5-kW use) or 20-amp (for 2-kW use)
GFCI outlets (don't cheap out and get regular
outlets...for safety's sake, spend the little bit of extra money)
- four 15-amp (for 1.5-kW use) or 20-amp (for 2-kW use)
SPST (single-pole single-throw) light switches
- 4-gang cover plates for the GFCI outlets and the switches
- a plug to match your outlet (This page shows
the different types of plugs and receptacles. Types 14-30P (1.5-kW
heatsticks only), 14-50P (1.5- or 2-kW), and 14-60P (ditto) would be easiest
and safest to get going. Types 10-30P (1.5-kW only) and 10-50P (1.5- or
2-kW) might work if you tie ground to neutral, but I'm not sure if this
would be considered safe practice and therefore can't recommend it at this
time. Types 6-30P, 6-50P, and 2-30P will definitely not work because they
don't provide a neutral connection and can therefore only provide
240V.)
- enough 10/4 (for 1.5-kW use) or 8/4 (for 2-kW use) SOOW appliance cord to reach from the outlet to your brewing
area, with a few feet extra (this is a thick rubber-jacketed cord with four
wires inside and offers a sufficient insulation breakdown voltage
(600V) to be usable on a 240V circuit)
- 15' of 14/2 (for 1.5-kW use) or 12/2 (for 2-kW use) Romex (or equivalent) solid-conductor cable (live and
neutral have their own insulation in this cable, but ground doesn't)
- four three-terminal blocks (you'll find these near the circuit breakers,
as they normally go inside breaker boxes)
- a package of 7" zip ties
- some #8 sheet-metal screws in 1/2" and 3/4" lengths
- a 1x2' piece of 3/4" particle board to serve as a base
For tools, you'll need screwdrivers, wire cutters, wire strippers, a razor
blade or sharp knife, long-nose pliers, a round file, and a drill and bits.
Disclaimer: I shouldn't have to put this in here, but if I didn't and
some numb-nuts got himself killed while trying to assemble or use this
device, his next of kin might hire an ambulance chaser to sue me into
oblivion. Since we haven't yet heeded Shakespeare's advice to kill all the
lawyers, take heed: This project involves wiring parts together that will
connect to a high-power electrical circuit (240 volts AC at 30 amps or
more). If you don't exercise sufficient care in assembly, testing, and use,
you could zap yourself. Construction is fairly simple, but if you have any
doubts about your electrical-wiring prowess, find somebody who is, or find
another homebrew construction project that doesn't involve electricity. I'm
not responsible for your errors; if you break something, you own both
pieces.
Start by cutting four 2' lengths of Romex. On each, strip back 3" of the
outer jacket and 1/2" of the insulation on the live (black) and neutral
(white) wires. Attach the wires to the corresponding terminals on a GFCI
outlet as shown (neutral goes to the "white" or "silver" screw, ground goes
to the green screw). Two 90° bends a short distance apart on the end of
each ground wire will provide a secure attachment, while the live and
neutral wires will probably go into holes in the back provided for that
purpose. Click any image for a closer view:
Feed the cables out one box and into the other, keeping the lengths in each
box approximately the same. The boxes will need to be mounted about an inch
apart, so keep that in mind. Bend the outlets out of the way so you'll be
able to screw in the outlet box:
Use four of the 1/2" screws to secure the outlet box to the board. Use a
3/32" bit to drill pilot holes:
Screw the outlets down into the box, carefully folding the cable underneath
so it doesn't get pinched:
In the switch box, use four 3/4" screws to secure the terminal strips as
shown. For added mounting strength, a couple of 1/2" screws elsewhere in
the box would be a Good Thing:
Strip back maybe 6" of the outer jackets. Pair up the ground wires (the
bare wires) from the left two positions and screw them to the #3 terminal
block (third over from the left). Do the same with the ground wires from
the right two positions. These need to be routed away from the other blocks
because the wires aren't insulated. Strip 1/2" of insulation off the
neutral wires (the white wires) and connect them to the #2 terminal block
(second over from the left) in a similar manner:
Carefully drill a 5/8" hole in the right side of the switch box (a spade bit
works well here); enlarge it with a file until the power cord just passes
through. Remove 9" of the outer jacket on the power cord and cut out the
paper separators. Feed the cable into the box and secure it inside and
outside with zip ties. Strip off 1/2" of insulation from each wire and
connect one wire to each block in this left-to-right order: red, white,
green, black:
Cut a 3' piece of Romex. Remove some of the outer jacket, grab the black
wire with pliers, and pull it out of the jacket. Cut the wire into four
equal lengths. Strip 3/4" of insulation off of each end, as well as on the
remaining wire ends in the box. For each of the left two circuits, connect
a wire from the box and one of the loose wires to a switch. Connect the
other ends of the loose wires to one terminal on the #1 block (the one with
the red wire in it):
Repeat for the right two circuits, with the loose ends connected to a
terminal on the #4 block (the one with the black wire in it).
Carefully fold the wires into the box and screw the switches down:
Install the cover plates with the screws included with each. Install the
plug on the end of the power cord according to the directions that should've
been packaged with it. When you're done, you should have something that
looks like this:
To test it, plug it in, flip the switches on, and reset all the GFCIs (they
come pre-tripped and won't reset if the wiring is screwed up). If you plug
a lamp in, it should light up. If you plug a heatstick in, it should get
hot.
The final part of the series includes "action shots" of the heatsticks and
power distribution board at work on their inaugural brew (an ESB that I hope
is reasonably close to
Fuller's).
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Scott Alfter; all rights reserved.
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