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What Size Consumer Unit Do I Need? (And Why It Matters)

August 12, 20253 min read

If you’re planning an electrical upgrade, adding new circuits, or just wondering whether your old fuse box is up to scratch — you might be asking:

What size consumer unit do I actually need for my home?

It’s a fair question — and the answer matters more than you might think.

First, What Do We Mean by ‘Size’?

When we talk about the size of a consumer unit, we’re really talking about the number of ways (or circuits) it can support.

Most homes in the UK have units ranging from 6 to 20 ways, depending on the size of the property and the electrical demands.

Each “way” is essentially a slot for a circuit breaker — so the more ways you have, the more circuits your consumer unit can handle.

So, What Size Is Right for You?

Here’s a rough guide based on what we typically see across Exeter and the surrounding area:

Home SizeRecommended WaysNotes1–2 Bed Flat6–8 waysBasic setup — lights, sockets, kitchen2–3 Bed House10–12 waysEnough for essential circuits + a few extras4 Bed+ or Renovated14–20+ waysRoom for modern additions like EV charging, outdoor lighting, extensions

But it’s not just about now — it’s about future-proofing.

We always ask:
👉 Are you planning a kitchen refit? An EV charger? Maybe an outdoor office or hot tub?
If so, we’ll recommend leaving room to grow.

Why Undersizing Can Be a Problem

We’ve visited homes where the consumer unit is already full — but the homeowner wants to add a new oven or garden office.

In those cases, it can mean expensive upgrades, or worse — people trying to double-up circuits (which is a big no-no and fails compliance).

A too-small board limits your home’s flexibility and could leave you stuck later on.

RCBOs, Dual RCDs, and Extras

It’s not just about quantity — it’s about layout. Today’s boards often come with:

  • RCBOs (Residual Current Breaker with Overcurrent Protection)

  • Surge Protection Devices (SPD)

  • AFDDs in some cases (especially in high-risk areas like rental properties)

We’ll always help you choose the right layout based on your home and the latest regs.

What We Recommend at EPM

When we replace a consumer unit in Exeter homes, we typically install a 12–16 way metal-clad board, even for a standard 3-bed house. That way you’ve got:

  • Plenty of space for current and future needs

  • Easier circuit management and labelling

  • Room for things like electric showers, induction hobs, or car chargers

This Is Where a Qualified Electrician Comes In

This isn’t a DIY job. Choosing and installing the right size consumer unit requires inspection and testing, knowledge of circuit loads, and understanding your household’s unique setup.

At EPM, we’ll assess your current system and make a recommendation that covers you not just for today — but for what your home might need in 5 or 10 years.

Final Thoughts

So — what size consumer unit do you need?

It depends on your home, your lifestyle, and your future plans. But one thing’s for sure: it’s not worth guessing. We’re always happy to take a look and give you honest advice (no pressure, ever).

Need a quick check or want to chat through your options? Give us a shout.

ConsumerMatters
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We provide fast, reliable, plumbing, heating, electrical, drainage and maintenance services for homes and businesses. Our team ensures your satisfaction with high-quality solutions.

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