CCR Step Current Reference | Precision AGL Academy

CCR Step Current / Brightness

Nominal and allowable output current for each L-828 / L-829 brightness step, with each step as a share of full current.

About this calculator

Choose the CCR class and number of steps to see the current each step should deliver. Enter a cable loop resistance to see the drop and loss at each step, or enter a clamp-meter reading to check it against the step it should match.

CCR Class, Steps & Cable

CCR output class

Brightness steps

Cable loop resistance (Ω) optional

Step Currents

Check a Measured Current

Measured output current (A rms)

Use a true-rms clamp meter on one conductor of the series loop. Compares against the steps chosen above.

CCR Step Current / Brightness Reference: Frequently Asked Questions

Quick answers on L-828 and L-829 step currents, tolerances and the measured current check.

What does the CCR Step Current / Brightness Reference show?

It shows the nominal and allowable output current for every brightness step of an L-828 or L-829 constant current regulator, with each step as a share of full current. You choose the CCR class and the number of steps. You can also enter a cable loop resistance to see drop and loss at each step, or enter a measured current to see which step it is closest to.

What are the step currents for a 6.6 A and a 20 A CCR?

A 6.6 A (Class 1) five-step CCR uses 2.8, 3.4, 4.1, 5.2 and 6.6 A, and a three-step unit uses 4.8, 5.5 and 6.6 A. A 20 A (Class 2) five-step CCR uses 8.5, 10.3, 12.4, 15.8 and 20 A. The step currents follow FAA AC 150/5345-10 (current edition H), where Style 1 is 3 steps and Style 2 is 5 steps. Confirm them against the edition in your specification and your CCR data sheet.

What is the allowable tolerance on each step current?

The output tolerance is plus or minus 0.1 A on a 6.6 A CCR and plus or minus 0.3 A on a 20 A CCR. The page shows the allowable range for each step by applying that tolerance to the nominal value. Check the edition named in your specification before using these figures as acceptance criteria.

Why is the 20 A three-step set marked as scaled?

The Class 2 three-step values of 14.5, 16.7 and 20 A are not an AC style in the FAA advisory circular. They are scaled values shown for reference only. The 5.5 A single step on a 6.6 A CCR is likewise a typical manufacturer option and not an FAA style, so confirm it with the CCR maker.

Does a percentage of full current mean the same percentage of light?

No. The percentage on the page is a share of current, calculated as the step current divided by the maximum current times 100. Light output falls much faster than current, and the relationship depends on the lamp or LED driver. Use the fixture photometric data for the actual intensity.

How much cable loss is there at the lower steps?

Cable loss follows the square of the current, so it is about 18 percent of the full-brightness value at 2.8 A on the 6.6 A class. The page calculates drop as V = I x R and loss as P = I squared x R from the cable loop resistance you enter. This applies to the cable only, because lamp and transformer loads change with current.

How does the measured current check work?

Enter a true-rms reading taken with a clamp meter on one conductor of the series loop. The page finds the nearest step for the class and step count you chose and shows the difference from nominal in amperes and as a percentage. It also tells you whether the reading is within the allowable tolerance. If the reading sits between two steps, the CCR may not be on the step you think.

What do the step names B1 to B5 and B10, B30 and B100 mean?

Five-step CCRs label the steps B1 to B5. Three-step units are commonly labelled B10, B30 and B100 on the control side, but the name for each step can differ between makers. Input power factor and efficiency also fall at low brightness by an amount that depends on the CCR design and loading, so use the data sheet for your model when sizing the supply.

Important Notice, Disclaimer & Limitation of Liability

Please read before relying on any content on this page or on any result or record produced by it.

Specific to this page: Applies to the CCR Step Current / Brightness (reference tool).

Calculated results. Results, tables, charts, status indicators (such as “OK”, “within limit” or “pass”/“fail”), recommended or selected values and the example presets on this page are first-pass planning and training estimates calculated in your browser from the values you enter, using simplified formulas, generic tables and typical values. They do not take account of every factor of a real installation, may contain errors or rounding differences, and are not a design, specification, selection, sizing, procurement or acceptance decision. A competent person must check them against the approved design, the manufacturer’s data and the applicable standard before any use. “Recommended” means an indicative estimate, not an endorsement of any rating, product or supplier.

Electrical values. Voltage, current, resistance, impedance, power, power factor, voltage drop, loss, load, capacity and efficiency figures depend on cable data, temperature, connector and transformer losses, CCR type, tolerances and other site conditions that a simplified calculation cannot fully capture. Default and example values are typical only. Do not rely on a result to load, energise, re-rate, tap or modify any circuit, CCR, cable or transformer.

Reference tables and conversions. Tables, step values, indication charts, unit conversions and other quick references are simplified summaries, may omit exceptions, tolerances and conditions, and may differ from the current official edition or from a particular manufacturer’s data. Check the source document before relying on any value. Converted values are rounded.

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Notice v2.9 · 27 October 2026 · Full terms: Legal & Disclaimer

CCR Step Current / Brightness

CCR Class, Steps & Cable

Step Currents

Check a Measured Current

How to Read This Table

Percent of full current

Cable drop and loss by step

Step names

Power factor at low steps

CCR Step Current / Brightness Reference: Frequently Asked Questions

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