I was mulling buying a powerline adapter, when I read this, from Which magazine.

There's one major caveat, however - powerline adapters won't work if your home electrical circuit is split over more than one ring. If your upstairs wiring is on a different electrical ring to your downstairs wiring, where your router lives, then you won't be able to extend the wi-fi upstairs using powerline adapters.

I'm not sure what this means, but I have a vague idea. The gateway is downstairs, the router I want to connect to is upstairs. They're on separate RCDs, which I assume means that they're on different rings... or does it?

I live in the UK.

  • Are you in the UK? or........... Does your house receive more than one phase of electrical power? Nov 9, 2017 at 19:33
  • I think the word "ring" is being used as a less technical term for "circuit."
    – BillDOe
    Nov 9, 2017 at 19:34
  • Yes, I'm in the UK. I don't know what you mean by phase, sorry.
    – Ne Mo
    Nov 9, 2017 at 20:25
  • Why don't these infernal contraptions tx/rx on the neutral or even better, ground lines! That would get around this uncertainty. Nov 9, 2017 at 20:52
  • The Which comment is false. If you have separate consumer units, it would be true. Although powerline adaptors are pretty flakey, anyway. Run some ethernet cable for stability; much cheaper too. Jan 28, 2022 at 22:24

1 Answer 1



Your quotation has a UK source. In the UK a "ring" refers to a ring-main also known as a ring-final circuit. This is the typical way UK houses have provided power to wall-sockets (outlets) since the 1950's.

They are called rings because they are connected in the topological equivalent of a large circle. There are two routes back to the consumer unit (main electrical distribution panel) from each socket.

diagram of ring main
Source: Wikimedia. CCASA 2.5 [email protected]. This example ring has two spurs.

Usually the ground floor has one ring-main and the upstairs has a separate ring-main. Anything larger than the average 4-bed detached might have more ring-mains.

Note that UK lighting circuits are separate and are not ring-mains, they are radial circuits. There will also be separate dedicated radial circuits for ovens/cookers, boilers and electric-showers.

Newer UK consumer units (main panels) have effectively a split power bus with an RCD for each half. So it is likely that there are RCDs between your downstairs gateway and your upstairs router.

Diagram of dual-RCD consumer-unit
Source: Chase Electrical. Headings above MCBs are: (downstairs) lights, sockets, cooker ... (upstairs) lights, sockets, shower. This example has a separate RCBO (combined RCD and MCB) for smoke alarms?


Across Different Rings

In my house I have an older arrangement that lacks RCDs in the consumer-unit. I use powerline networking between my upstairs router and my downstairs TV (it provides much better throughput and greater reliability than using WiFi in my specific circumstances) - So powerline networking can span rings.

Across RCDs

I don't know how much trouble (if any) your RCDs will cause. Anecdotal evidence suggests you might experience any of

  • it works but you lose around 20Mbps of 85Mbps bandwidth. or
  • it doesn't work. or
  • it trips the RCD.

What to do

I would go to a shop, clearly explain that I want to use the powerline units on separate rings each on a separate RCD. If they sell me some units for that scenario and they don't work, I would promptly return them as not "fit for purpose" under UK law (consumer rights act 2015).

(1)Subsection (3) applies to a contract to supply goods if before the contract is made the consumer makes known to the trader (expressly or by implication) any particular purpose for which the consumer is contracting for the goods.


(3) The contract is to be treated as including a term that the goods are reasonably fit for that purpose, whether or not that is a purpose for which goods of that kind are usually supplied.


(for Harper)

MCBs labelled

Ring final circuit test

  • Wait. Suppose the wire you're using in that ring is legal for a 15A radial circuit.... do you breaker it for 15A or 30A? Nov 9, 2017 at 21:10
  • @Harpur: See addendum to answer. A UK ring-main is protected by a 32A breaker. The wiring is 2x2.5 mm² (~14AWG?). Breaks in the ring would be a bad thing. Nov 9, 2017 at 21:35

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