Introduction
3 phase RCBOs are essential for protecting circuits in three phase installations, but not every RCBO advertised as “3 phase” is actually one. Some sellers incorrectly market 10kA, single module, single pole RCBOs as “three phase devices” — which is misleading. In reality, those are single phase RCBOs designed to fit into three phase distribution boards.
This guide clears up the confusion, explains what a true 3 pole RCBO is, and highlights genuine products from Live Electrical, Niglon, and Hager.
Table of contents
What Is a True 3 Pole RCBO?
A genuine three phase RCBO combines the functions of a miniature circuit breaker (MCB) and a residual current device (RCD). Unlike single pole RCBOs, which only protect one circuit, a 3 pole device protects all three phases together.
Key characteristics include:
- Three switching poles (L1, L2, L3).
- Combined overload, short circuit, and earth leakage protection.
- Designed for industrial distribution and commercial distribution.
This makes them ideal for machinery, HVAC, and large installations where balanced three phase loads are in play.
The Common Misunderstanding
Many wholesalers list single module, single pole RCBOs as “three phase RCBOs.” While these fit into a three phase distribution board, they only protect one phase/circuit at a time.
For example:
- A single pole 10kA RCBO in a 3 phase board = single phase protection.
- A 3 pole RCBO = true three phase protection across all lines simultaneously.
Important distinction: one-pole does not equal three-phase.
Live Electrical Three Phase RCBOs
Live Electrical 3 phase RCBOs are compact, installer-friendly, and available in multiple ratings. They are designed specifically for Live Electrical TPN boards, making them a straightforward choice for contractors who already use Live distribution gear.
Features include:
- Wide range of amperages.
- True 3 pole switching.
- Compliance with BS EN standards.
Niglon Three Phase RCBOs
The Niglon 3 phase RCBO range is ideal for heavy-duty applications. They offer excellent durability and are compatible with Niglon Protego 125 boards.
Highlights:
- ON–AUTO–OFF facility.
- LED indication for clear fault status.
- Supplied with a 9mm vented spacer.
- BS EN 60947-4 compliant.
These make Niglon a trusted option for commercial electricians.
Hager Adaptors and 3 Pole MCBs
Hager does not currently manufacture a standalone 3 phase RCBO. However, they provide the Hager BD163T adaptor, which, when paired with a 3 pole MCB, creates a functional three phase RCBO assembly.
This hybrid solution provides:
- Overload and short-circuit protection (via the MCB).
- Residual current protection (via the add-on RCD).
- Full coverage across all three phases.
It’s a clever modular approach for electricians who prefer Hager’s quality distribution boards.
Why Accuracy Matters
Getting this terminology right matters:
- Prevents confusion when sourcing protection devices.
- Ensures compliance with the 18th Edition wiring regulations.
- Helps electricians avoid mistakenly using single pole devices where 3 pole protection is required.
At Electrical4Less, we only list true three phase RCBOs under our 3 phase RCBO category. This ensures you can order with confidence, without worrying about misleading descriptions.
FAQs – Three Phase RCBOs
Can a single pole RCBO protect a three phase circuit?
No — it only protects one phase within a board
What makes a 3 pole RCBO different?
It combines overload, short circuit, and earth leakage protection across all three lines simultaneously.
Does Hager sell three phase RCBOs?
Not directly, but with the BD163T add-on and a 3 pole MCB, you can create a functional solution.
Which brands supply genuine products?
Live Electrical and Niglon both manufacture true 3 pole RCBOs.
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3 Phase RCBOs Explained: What They Really Are