Work at Tank Farm #2

Power Transformer / Panel #1

On a newly-poured concrete slab, I mounted a Unistrut rack;  set the 75 kVA transformer, disconnect & 100-Amp panel;  and did grounding for the derived system (2 ground rods and piping, as shown).

Bent, cut, threaded & ran the underground 1" & 1-1/4" HW conduit (1 for the 480V supply, 3 for 120/240V heat trace loads).

Connected the supply conduit to a new 24x24x8" junction box, and from there ran 300 feet of 2" HW conduit to tap into an existing junction box containing a 200-Amp feeder:

(All by myself, except running the 2" conduit and pulling the wires.)

Ran conduit, installed thermostats, pulled circuits & connected the Heat Trace:

(The new 2" conduit & junction box can be seen at the bottom of the first image.)

Tank #1 Power

On a concrete pad they poured, I installed a Unistrut rack, a 15×18×8" junction box, a 8×8×72 gutter, and a 25 H.P. motor starter.

Bent, cut, threaded, and installed the supply conduits into the junction box (2" HW for 480V/200A power, 1-1/4" HW for the heat trace);  and the 2 x 1-1/4" HW conduits out (1 for 480V motor leads, 1 for heat trace & control wiring):

(Ran parts of conduits at 84" above grade, as requested, to allow maintenance access.)
(I recommended this long gutter -- in order for future starters to be installed, to the right.)
(Typically my Supervisor told me generally what he wanted, then I did the layout, gave him parts lists every day or two, and installed most of it myself.  I had a helper to hang the gutter and pull the wires.)

Continued the two 1-1/4 HW conduit runs for the motor & heat trace.
Did GRX's as needed for the thermostat & to the heat trace at the top of the tank:

(Ran the conduit by myself, with a boom lift;  pulled the wire with a helper.)

Stopped one 1-1/4" HW conduit at a new reversing switch, and ran new 1-1/4" conduits to the motor and VFD:

(Bypassed the reversing switch, after I installed the VFD.)

The second 1-1/4" HW conduit for heat trace ends at a 1-1/4" GRX (can be seen in the above picture).  Installed 3/4" HW, GRX's, thermostats, etc. to connect to existing & new heat trace:

T35-HT.jpg   T35-HT-2.jpg   T35-HT-3.jpg
Note the 240V "Indicator Lights" (black cap & clear cover), which light when the thermostat is calling for heat.

Tank #1 VFD

New VFD I installed for a 25 H.P. motor.  First I had to redo the Unistrut rack, and move an existing starter a few inches to the right:

T35-VFD(R).jpg   T35-VFD-Wired.jpg
Note the “FORward / OFF / REVerse” switch, and the speed control dial on the cover;  and also the 120V cooling fan on the left side, powered by the 480-120V transformer.

Wrote instructions for the Operators to use the VFD:  (Can be seen in the above picture, hanging above the “Start / Stop”)

(Got it laminated by a copy shop)

Power Transformer / Panel #2

On a concrete slab we set in place with a skidsteer, I mounted a Unistrut rack, and set the 75 kVA transformer, disconnect & panels.  Bent, cut, threaded & ran 1-1/4" HW conduit (1 for 480V supply, 2 for 120/240V heat trace loads):

LVP26-Rough.jpg   LVP26-UG.jpg   LVP26-UG-South.jpg
(The underground runs end at a new 24x24x8" junction box I installed.
From this box, I ran 10' of 2" HW to a supply box, and 2 x 50' of 1-1/4" HW for heat trace.)

VFD #3

The third VFD I installed:

T16RR-VFD-Rough.jpg   T16RR-VFD-Wired.jpg

VFD Enclosures

For each VFD I used a 15×12×10 “Nema 12” enclosure, sized to fit the VFD and its associated equipment.

With a Metabo, I cut the holes for the viewing window (to see the readout with the cover closed), and for a cooling fan (fan / exhaust on left, intake on right). Used a 3/4" KO punch for the control switches, and a die grinder to bump them up to 30mm:

(Idea, layout, cutting & all installation & wiring by me.)

Arc Flash

Did site-wide “Arc Flash” calculations as per NFPA 70E.

At all equipment required to be labeled, I installed NFPA 70E-compliant Arc Flash labels:

(They bought a label printer;  I typed out and installed the labels where required.)

Risk Assessment

Did a preliminary NFPA 70E “Electrical Hazard Risk Assessment”, documented the results & submitted to management:


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authored:  29 March 2015

last revised:  25 April 2016