Meter isolator switches cause a lot of head scratching on site. Is it just another main switch? Why 2 pole on some installs and 4 pole on others? This guide cuts through the jargon and explains exactly what a 4 pole meter isolator switch is, when it’s required, and how it keeps your install safe and compliant.
Jump to: What Is a Meter Isolator Switch? | Why Choose a 4 Pole Isolator? | Where Is a Meter Isolator Installed? | Compliance & UK Regulations | FAQs | Recommended Product
What Is a Meter Isolator Switch?
A meter isolator switch provides a safe way to disconnect the incoming supply between the electricity meter and the consumer unit. Unlike an MCB or RCBO, it does not protect against overloads or faults - its job is purely isolation. This allows electricians to safely carry out upgrades, maintenance, or testing without relying on the DNO to pull the fuse.
Why Choose a 4 Pole Isolator?
Not every install needs four poles - but when you’re dealing with three phase supplies, it’s non-negotiable. A 4 pole isolator ensures every live conductor, including the neutral, is disconnected in one action.
- 2 Pole: Disconnects phase and neutral on a single phase supply.
- 4 Pole: Disconnects three phases and neutral - required on three phase systems.
If you’re working on commercial or larger residential setups with three phase supplies, a 4 pole isolator is essential. It ensures all live conductors can be disconnected in one operation.
Where Is a Meter Isolator Installed?
The isolator sits between the meter tails and the consumer unit:
- Installed on the meter board, meter box, or adjacent wall.
- Provides safe isolation for consumer unit replacements or upgrades.
- Sometimes fitted by the DNO, but often supplied and installed by the electrician.
Compliance & UK Regulations
Meter isolators fall under BS EN 60947-3, covering switch disconnectors. Key points:
- Safe means of isolation: Required under the 18th Edition.
- PME / TN-C-S systems: Full disconnection of all conductors is often necessary, making 4 pole the safer choice.
- Rated for duty: Ensure the isolator is correctly sized - typically 100A for standard installs.
FAQs
Installers and buyers often have the same questions about meter isolators. Here are the key answers - clear, compliant, and straight to the point.
What is the difference between a meter isolator and a main switch?
A meter isolator is fitted between the meter and the consumer unit. A main switch is part of the consumer unit itself. Both provide isolation, but they’re in different locations and serve different purposes.
Do I need a 2 pole or 4 pole isolator?
Use a 2 pole isolator for single phase supplies. Use a 4 pole isolator for three phase supplies where all conductors (L1, L2, L3, N) must be disconnected together.
Is a meter isolator switch mandatory?
Not in every case - some DNOs fit them as standard, others don’t. Many installers fit their own to simplify future upgrades and provide safe, local isolation.
Can I fit a meter isolator myself?
Installation must always be carried out by a qualified electrician. The isolator connects directly to live meter tails, which can only be worked on safely with the correct training and equipment.
Recommended Product
Looking for a trade-ready unit? Check out our best-selling isolator:
Conclusion
A 4 pole meter isolator switch isn’t about fault protection - it’s about giving you safe, compliant disconnection on three phase supplies. Whether you’re upgrading a consumer unit or wiring a new commercial board, it’s the essential link in the chain.
👉 Order your 4 Pole Meter Isolator today - UK-stocked, compliant, and ready to fit.