HomePlugs and RCDs

[Invisible Man]

We use a fairly basic homeplug for occasional use of an old PC upstairs in the opposite corner of the house.

We have a TT system with a split load box with each side having its own RCD. The upstairs power ring is on a different RCD from the downstairs ring. There has been some discussion here on whether this is a problem.

Unscientific and as reported by PowerPacket Utility:

Plugged in beside the upstairs PC speed is about 28Mbps

Plugged in to a socket the other side of the room about 32 to 40Mbps

Plugged into the light socket which is on the same RCD as the downstairs power ring about 48 to 65Mbps

It does therefore appear that the RCDs do make a difference unless anyone has any alternate suggestions.

All figures tend to reduce in the evenings. No extra electronics on but there are lights.

[John Rumm]

My experience would support that also...

The answer to the question "do they work through RCDs?" being a definitive "yes". However you can expect some loss of performance.

What I can't really qualify as yet is whether its the RCD in particular or the MCB which has the effect, or just the migration to another circuit etc. Empirical tests would suggest they all play a part - in that throughput on one circuit only tends to be better from one to another on the same RCD, which is still better than to another on a different one.

[mick]

All the mcbs that I've seen use a series electromagnet for overcurrent trip (I have a clear plastic demo one which shows this clearly). I suspect that most RCDs are the same for the overcurrent part, so between two RCD circuits you effectively have two series inductors. I'm pretty sure that will do something nasty to data speeds, particularly in conjunction with cable capacitance.

Also, any high efficiency lamps will introduce some waveform problems on the supply, possibly along with some noise while they are on. That won't help either.

Because the inductors would probably introduce some degree of attenuation between the two protected circuits, I suspect that you could treat each circuit separately and that results on each may not be the same - depending on connected loads, lengths of cable etc.

[Invisible Man]

To get to the upstairs power ring the signal has to traverse 2 mcbs and

2 rcds. To get to the upstirs light ring the signal has to traverse 2 mcbs.

Downstairs circuit has 2 TVs, 2PCs and peripherals connected. Upstairs circuits had nothing electronic on them at the time.

[Dave Liquorice]

Interesting comment.

Are the lights CFL's or tungsten? Does the speed recover if you switch the lights off? I doubt it will but be interesting to know.

Homeplug uses up to 1155 carriers between 1.8 and 30MHz. At night the "noise" level from broadcast and other stations in that frequency range will increase. Just like LF and MF broadcast stations increase the noise level for ADSL at night.

[jkn]

A little off-topic...

Are there any Homeplug adapters which provide a mains outlet and the ethernet receptacle in one housing? So that for example you could connect a NAS to a Homeplug network via a single mains outlet? All the adapters I've seen 'use up' a mains outlet, which seems a shame.

Thanks for any pointers.

J^n

[Invisible Man]

No CFLs on upstairs lighting circuit. Never on for long and need full brightness as soon as they are turned on. There are however a couple of CFLs on the downstairs power ring. A quick test suggests they reduce speed by about 5 percent.

[T i m]

Interesting.

I did get round to getting / fitting the Homeplugs (the std speed ones) at our friends (long, was two houses) house and saw about

9-10Mbps when at full stretch (14M when plug side-by-side).

I wasn't sure if the faster units would suffer a greater loss than the slower ones (and hence why I went for them). Plus, I'm not sure how often they would really see 20Mbps on their VM BB?

Cheers, T i m

[John Rumm]

[Dave Liquorice]

Yes, I've seen them fairly recently on the web. One a "wall wart" type the other a "dalek" with, IIRC 4 ethernet ports and 6 mains outlets.

Have a look at the Solwise site.

[jkn]

trawls.

J^n

[John Rumm]

Sounds like the "Piggy 6"

Indeed:

[Steve Walker]

[mick]

Nasty, vile things. They aren't bothered about which frequencies they screw up either. Most of the Amateur bands are between those frequencies and homeplug stuff can obliterate all reception at several tens of metres away from the house!

[Dave Liquorice]

Apart from the tuft of mains cables you'll have sticking out of the top of the thing. WTF couldn't they have two rows of three offset so the cable from the top row passes between the plugs on the lower row.

If the AV kit that requires network connections appears here I think I'll be going for the Netgear XAV1004.