Why RCBOs matter
What is residual current (earth leakage) protection?
Standard circuit breakers do a great job of protecting against overloads and short circuits -but they offer no protection against electric shock. That’s why residual current protection is needed.
It works by comparing the current going out to a load with the current returning. If everything’s fine, those values match exactly. But if the returning current is slightly lower, it means the difference must be going somewhere else – possibly through someone’s body. That’s when the protection kicks in and cuts the power. In most countries, electrical regulations require residual current protection on all circuits rated 32A or less, and the maximum permitted leakage is 30mA (milliamps).
Limitations of shared RCDs in professional AV power systems
In a typical home, you probably have one or two residual current breakers (RCDs) protecting several circuits at once. That usually works fine for domestic applications. But when powering modern AV equipment, things get more complicated.
Modern AV gear – especially LED lighting, video walls, and media servers – uses switch-mode power supplies. These are efficient and compact, but they also generate high-frequency electrical noise. To stop that noise from leaking out onto the electrical grid, the devices are fitted with filters that divert it to ground.
This means a small amount of the incoming current doesn’t return – it “leaks” to earth. That’s what we call residual current, and even though it’s completely harmless, the RCD can’t tell the difference between that and a life-threatening fault.
Each device can leak up to 3.5mA, and although it’s usually a bit less, it quickly adds up across multiple devices. To make things worse, a 30mA RCD is allowed to trip at just 15mA and still be within spec.
Conventional RCD setup – one trip affects multiple circuits.
Why residual current can trip your system – even without a fault
Using a single RCD to protect multiple circuits is completely legal -and commonly done – but it comes with real drawbacks.
With this setup, you only get an average of about 5mA (30mA ÷ 6) of “safe” leakage per circuit. That’s not much room to work with. And when the RCD trips, everything it protects goes down. You’re left trying to figure out which circuit – or combination of circuits – caused the trip. It’s slow, disruptive, and not ideal for live or critical environments.
The advantages of using RCBOs in AV power distribution
Fortunately, there’s a much better solution: the Residual Current Breaker with Overload protection, or RCBO.
An RCBO combines a standard circuit breaker with residual current protection in a single unit – per circuit. That means if something goes wrong, only that one circuit is affected. The rest of your system keeps running, and you instantly know where the issue occurred.
RCBO setup – each output is independently protected.
Why StageSmarts uses Hydraulic-Magnetic RCBOs
We’ve used hydraulic-magnetic RCBOs in all our power distribution systems since 2017. Thousands of systems are in use globally today, protecting gear and people in tough, high-stakes environments. Our RCBOs are:
1P+N, meaning both the live and neutral conductors are disconnected when the RCBO trips, fully isolating the load.
Rated at 30mA, Type A, which is ideal for modern AV equipment. These RCBOs can handle the harmless residual currents from switch-mode power supplies without nuisance tripping.
Hydraulic-magnetic, so they’re unaffected by temperature, and capable of handling the high inrush currents from amplifiers, LED panels, and other demanding loads.
Many users report they can power twice as many devices per output compared to previous systems. That’s because our RCBOs provide true individual protection, eliminate shared residual current issues, and cope better with startup surges.
Smarter residual current protection for demanding environments
Residual current protection is a must – but how you implement it makes a big difference. With our approach, each output is protected individually. You get better fault isolation, fewer unnecessary shutdowns, and a system that’s easier to work with, even when the pressure’s on.
