⚠️ Safety First

• RCD trips indicate earth leakage. This procedure is a temporary soft‑start/sequencing method to get up and running for today. Log the incident and book a service call with Solid to investigate permanent fixes (inrush management, staged power, etc.).
  

• Why this happens

  • Not always a fault: A single trip on a very cold or damp morning doesn’t automatically mean there’s a permanent fault. Large switch‑mode power supplies (PSUs) have input EMI filters and big charging capacitors. When many PSUs start at once:

    • Their Y‑capacitors to earth create a small leakage current each; the sum across dozens of PSUs can momentarily exceed a 30 mA RCD threshold, especially if there’s condensation increasing surface leakage.

    • Cold electrolytic capacitors and PFC front‑ends draw brief, peaky currents while charging; this can nuisance‑trip upstream protection and coincide with RCD sensitivity.

  • Why sequencing helps: Bringing circuits up one at a time reduces the number of PSUs energising simultaneously, which cuts the instantaneous leakage/inrush and also helps identify any sub‑circuit that is genuinely leaky or damaged.

Soft‑Start Procedure (Sequenced Power‑Up)

Objective: Bring circuits up one at a time to avoid a big inrush.
We are using an example of an LED screen with 4 rows of LED panels/cabinets (top, middle, bottom, plus a misc. circuit). Your configuration will most likely be different.
If you are nervous about this procedure then STOP and contact your organisation's Sparky (licenced electrician).

1. Power Down & Reset

   • Turn OFF the Main Isolator.
     
     

   • Ensure all MCBs (Top/Middle/Bottom/Misc) are set to OFF.

   • Set RCD(s) to OFF/RESET (down) as applicable.

   • Wait 60 seconds to allow supplies to discharge.

2. Energise RCD(s)

   • Turn ON the RCD(s) (safety switches). Confirm they stay latched.

3. Sequenced MCB Power‑Up

   • Turn ON the Main Isolator.

   • Turn ON MCB #1 (e.g., TOP ROW) and wait 10–15 seconds.

   • If no trip, turn ON MCB #2 (e.g., MIDDLE ROW). Wait 10–15 seconds.

   • If no trip, turn ON MCB #3 (e.g., BOTTOM ROW). Wait 10–15 seconds.

   • Finally, turn ON MCB #4 (MISC/AUX). Wait 10–15 seconds.

   • Observe the screen; confirm normal boot with no trips.

4. If an RCD Trips during Sequencing

   • Note which MCB you just turned on.

   • Set Main Isolator OFF.

   • Set the last MCB back to OFF.

   • Turn RCD ON (reset). Turn Main Isolator ON.

   • Skip the problem MCB and continue bringing others up one‑by‑one to run the rest of the screen for today.

   • Log the tripping MCB name (e.g., “MIDDLE ROW”) for service.

Isolation Procedure (Find the Faulty Sub‑Circuit)

Objective: Identify which circuit is causing the trip so we can operate the remainder safely.

1. All OFF: Main Isolator OFF, all MCBs OFF, RCD OFF/Reset.

2. RCD ON: Turn on RCD(s) and confirm they latch.

3. Main Isolator ON.

4. Turn on MCBs one‑by‑one with a 10–15 sec pause between each:

   • If a trip occurs immediately after a specific MCB, mark that MCB as Suspect.

   • Reset as above, leave the Suspect MCB OFF, and continue with the remaining circuits.

5. Operate with Suspect MCB OFF for today. Book service ASAP to diagnose that row/section.
   

1. Operating an LED screen with a non-functional circuit will most likely affect other portions of the screen image & the daisy-chained video feed. 

When to Stop and Call for Help

• An RCD won’t latch even with all MCBs OFF.

• Repeated trips on the same MCB after sequencing.

• Visible moisture inside enclosures, damaged cables, or burning smell.

• Any signs of electric shock, smoke, arcing, or heat damage.