How do you calculate test bay capacity?

Multiply units per cycle by available cycles for gross capacity, then multiply by uptime and yield. With 4 units per cycle, 480 cycles, 90 percent uptime, and 97 percent yield the good output is 1,676.16 units.

What is the difference between gross and good capacity?

Gross capacity here is 4 x 480 = 1,920 units, the theoretical maximum. Good capacity is what actually ships after 192 units of uptime loss and about 51.84 units of yield loss, leaving 1,676.16.

What is a good test bay uptime?

Well-run final-test bays run 85 to 95 percent uptime; the 90 percent default is typical. Time is lost to setup, calibration, fixturing, and waiting on units from the build floor.

How does first-pass yield affect capacity?

Every failed unit consumes a cycle but does not count as good output, so a 97 percent yield trims about 51.84 good units off the uptime-adjusted total in the example. Improving yield frees real capacity.

Should retested units be counted?

Not as new good units. A retest consumes another cycle, so persistent rework effectively lowers your usable cycles; model that by reducing available cycles or yield rather than double-counting.

How do I find the bottleneck between build and test?

Compare good test capacity against build-line output. If test good capacity (1,676 here) is below build output, the test bay is the constraint and the candidate for a second shift or bay.

Switchgear, Panelboards & Electrical Distribution calculator

Test Bay Capacity Calculator

Test bay capacity tells a switchgear plant how many fully-tested, passing assemblies it can push through final electrical testing in a given period. Production planners and test-lab supervisors use it to schedule ship dates, spot the bottleneck between build and test, and decide whether a second bay or shift is needed. Because dielectric, primary-injection, and functional tests are often the last gate before shipment, this station frequently sets the true plant throughput. The calculator takes gross capacity and discounts it by bay uptime and first-pass yield to give a realistic good-unit output.

What this calculator does

Test bay capacity tells a switchgear plant how many fully-tested, passing assemblies it can push through final electrical testing in a given period.
Use it when test bay capacity in switchgear, panelboards and electrical distribution is being asked to take on more work and you need to know if there is room.
It computes good-unit test throughput by multiplying units per cycle and available cycles, then discounting for uptime and first-pass yield.

Formula used

Gross test bay capacity capacity = units per cycle × available cycles
Good capacity = gross capacity × uptime × yield

Inputs explained

Units tested per bay cycle:
Available test cycles in the period:
Test bay uptime:
First-pass test yield:

How to use the result

Use it for capacity planning, ship-date commitments, and deciding when to add test bays or shifts on a switchgear line.
It assumes a steady cycle time and one uniform product; mixed models, rework loops, and retest of failed units are not modeled directly.

Current U.S. benchmarks

The producer price index for copper and brass mill shapes stands at 559.593 (BLS, May 2026), up 76.8% from a year earlier. Quotes priced off last quarter's material cost miss this move. Global copper trades at $13,484 per tonne (IMF via FRED, May 2026).
Industrial electricity averages 8.66 cents per kWh across the U.S. (EIA, Apr 2026), up 5.5% from a year earlier. Energy-intensive steps carry this directly into unit cost.
On-highway diesel averages $4.58 per gallon this week (EIA), trending down over recent periods. Truck tonnage is up 3.4% year over year (ATA via FRED).
The U.S. has 21,668 machinery manufacturing establishments employing about 1,086,146 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate test bay capacity? Multiply units per cycle by available cycles for gross capacity, then multiply by uptime and yield. With 4 units per cycle, 480 cycles, 90 percent uptime, and 97 percent yield the good output is 1,676.16 units.
What is the difference between gross and good capacity? Gross capacity here is 4 x 480 = 1,920 units, the theoretical maximum. Good capacity is what actually ships after 192 units of uptime loss and about 51.84 units of yield loss, leaving 1,676.16.
What is a good test bay uptime? Well-run final-test bays run 85 to 95 percent uptime; the 90 percent default is typical. Time is lost to setup, calibration, fixturing, and waiting on units from the build floor.
How does first-pass yield affect capacity? Every failed unit consumes a cycle but does not count as good output, so a 97 percent yield trims about 51.84 good units off the uptime-adjusted total in the example. Improving yield frees real capacity.
Should retested units be counted? Not as new good units. A retest consumes another cycle, so persistent rework effectively lowers your usable cycles; model that by reducing available cycles or yield rather than double-counting.

Last reviewed 2026-05-12.