At nine a fitter builds a catalogue TPN distribution board he has made a hundred times. At eleven he starts a special: a feeder pillar for a housing project with a larger incomer, top cable entry and an extra metering chamber. At four the special reaches the test bench with the incomer busbar in the catalogue section and the gland plate punched for bottom entry. Nothing about the fitter's skill changed during the day. His habits simply followed him from one job to the next.
This is the main pressure point for makers of distribution boards, feeder pillars, meter boxes and busway. The product range sits half in a catalogue and half in custom drawings, and the same people build both. Every switch between them is a chance for the familiar to overwrite the drawing.
Why switching causes errors
A catalogue board is built from memory. The fitter barely looks at the drawing, because the layout, busbar sizes and wiring are routine. That fluency is what makes catalogue work fast. On a special, the same fluency becomes a trap. The hands reach for the usual busbar length, the usual MCCB from the rack and the usual gland position before the eyes have checked the drawing. The more catalogue boards a fitter has built, the stronger the pull.
The errors that follow
- Busbar section or length taken from the catalogue size on a special with a higher incomer rating.
- Cable entry punched on the usual side, when the site needs top entry.
- Breaker rating or frame picked from stock for the catalogue board rather than the special's schedule.
- Neutral and earth bars sized as standard on a board with heavier neutral loads.
- Shrouding and phase barriers left off because the catalogue model does not use them.
- Labels and ferrules copied from the standard board's legend sheet.
What it costs
Errors caught at the test bench cost a strip-down and an evening. Errors found on site cost a crew visit and, on tender work, a delay clause. There is also a people cost. Fitters who handle specials well become precious and overloaded, estimators price specials as if they were catalogue boards, and the floor carries hours that were never in the quote.
Fixes that take the switch out of memory
- 1
Make specials look different
Print special job cards on a different colour and hang a SPECIAL tag on the enclosure from the punching stage onward.
- 2
Issue a delta sheet with every special
The drawing engineer names the nearest catalogue board and lists only what differs. Fitters read the differences, not a full drawing they half-remember.
- 3
Kit specials in stores
Stores picks busbars, breakers, shrouds and glands for the special into a separate tray against the BOQ, and somebody else ticks the tray off.
- 4
Check the first stage
A checker inspects busbars and breakers on a special before wiring starts, while a correction still takes minutes.
- 5
Route specials to graded fitters
Specials go to fitters cleared for special drawings, with a junior beside them to learn.
- 6
Batch where dates allow
Group specials onto set days or into one bay, rather than alternating board by board.
- 7
Brief the day's specials at start of shift
Five minutes on what is different about each special on the floor today.
JOB: ______ CUSTOMER AND SITE: ______ DRAWING AND REVISION: ______.
NEAREST CATALOGUE BOARD: ______.
DIFFERENCES ONLY: incomer rating and frame ______ | busbar section and length ______ | neutral and earth bar ______ | cable entry (top or bottom) ______ | outgoing count and ratings ______ | metering ______ | shrouds and barriers ______ | enclosure size and colour ______ | labels ______.
KIT CHECKED IN STORES BY: ______.
FIRST-STAGE CHECK (busbars and breakers) BY: ______.
FITTER HAS READ THIS SHEET: signature ______.Fitters, grades and estimators
Fitters who read special drawings well are scarce and are courted by larger panel builders. Grade them openly: catalogue assembly, special drawings, then leading a job. Pay the grades against nearby shops using the board maker pay benchmarking page. Bring estimators onto the floor once a month to compare quoted and booked hours on specials, so the next price reflects reality. Tender peaks and overtime planning are covered on the board maker shift and leave page.
Where to start
- Sort last month's test bench rejects into catalogue and special.
- Count the fitters who can build from a special drawing alone.
- Ask stores whether specials are kitted separately today.
- Look at tomorrow's plan and see how many times a fitter switches between catalogue and special work.
Dust, noise and live-work routines for punching, coating and assembly bays are on the board maker health and safety page. The power distribution equipment makers page names further strains such as site trips and estimator gaps. For how board makers compare with panel, switchgear and transformer shops, see people challenges in electrical equipment manufacturing.
