Driver MCB calculator

How many LED drivers can share one circuit breaker, from inrush and running current.

Find it on the driver datasheet under "Quantity of drivers per miniature circuit breaker 16 A Type C". Where it says ">100 pcs", type 100 or more. The tool scales it to the breaker you picked.

Under "Mains characteristics" on the datasheet. Where it gives a range, use the top of it.

0.76 is the factor in Helvar Components' datasheet example (many breakers side by side, 30 degrees C ambient). Use a higher figure only if your installation allows it.

 

Driver
Breaker
Drivers per breaker, from inrush
Drivers per breaker, from continuous current
Governing limit
Drivers per breaker used
Breakers needed
Drivers on the last breaker

How this is worked out

Each breaker takes the smaller of two limits. Breakers needed is the driver count divided by that, rounded up; the last breaker carries the remainder.

Limit 1: inrush

  • At switch-on each driver draws a short, large pulse. Enough of them add up and trip the breaker, even though the running current is fine.
  • The datasheet gives how many drivers a C 16 A takes. Other breakers use Helvar's conversion table: B10 37 %, B16 60 %, B20 75 %, C10 62 %, C16 100 %, C20 125 %.
  • Rounded down.

Limit 2: continuous current

  • A breaker shouldn't run at its full rating all day, especially packed in a warm board.
  • Helvar's formula: drivers = (breaker rating / mains current at full load) x 0.76, rounded down.
  • The B or C curve doesn't change this limit.

B or C curve

  • Type C suits LED drivers: a Type B takes 40 % fewer drivers on inrush at the same rating.
  • IEC 60898: Type B trips instantly at 3 to 5 x rated current, Type C at 5 to 10 x.

Sources and defaults

  • Helvar Components datasheets for LL120HE-DA-100-800 and LC45SE-DA-150-1050-LOOP: the inrush and conversion tables, the 0.76 factor and the defaults (27 drivers on C 16 A, 0.58 A). Change them for your driver.
  • Helvar's figures assume ABB S200 breakers. Other makes differ; check their documentation.
  • 13 A isn't offered because the conversion table only covers 10, 16 and 20 A.
  • Find your driver in linear or compact LED drivers.

Results are a planning aid, not a design sign-off. Check the figures against the manufacturer's datasheet for the exact product, or ask us to check them with you.IP Geolocation by DB-IP