Has anyone invented...

[dextrous]

Picture the scenario. We are renting out a house with self contained bedsits. Originally being a domestic house these are cabled using several ring circuits (one per floor, each floor has two or three bedsits on them).

At present, we charge an all inclusive rate for electrics, heating etc, but some of the tenants run additional fan heaters since they like it warm.

So, now to the point of all this. Has anyone invented something that would replace the current sockets with others that incorporate a way of measuring electricity usage. I'm talking about something along the line of each socket having it's own "address" (like a network), which provides data feedback to a computer type thingy.

Thus a for a room with say 4 double sockets would provide 4 data feedbacks from which the total use of electricity could be logged, and the tenant charged pro rata accordingly.

If not invented yet, then would this be impossible (I feel a dragon's den coming up here)? I'm sort of basing the concept along the lines of some computer networks using the existing mains circuits to carry it's data along. It would be cheaper and less invasive to install than rewiring with individual room meters/card/coin slots etc.

Or should I just have an early night?

 

[ColJack]

card meters or an early night...

 

[dextrous]

card meters or an early night...

But card meters require individual room circuits, do they not?

 

[ColJack]

yes and / or no..

it's possible to fit them on a radial to meter the sockets downstream, but not a ring since it then becomes an interlinked ring ( figure 8 )...

easiest way would obviously be a seperate circuit to each room and take the light off a fused spur ( or install a mini-CU for each room )

you may be able to take the sockets in each room and split the ring into smaller rings for use on the new circuits rather than a total re-wire..

 

[plugwash]

Have you actually traced the wiring and worked out how much you would need to change to split things up? depending on how the wiring runs it may be less than you would think. Remember the individual room circuits don't have to be rings, a 20A radial should be ok for a one room bedsit.

 

[dextrous]

Yep, I know exactly how the circuits go, as I was a cable monkey for the spark who fitted them (to help keep costs down at the time!!). Splitting the rings into radial would be a complete nightmare, hence my desire for a brand new approach.

Wish I had the cash to develop the system I'm talking about, as I'm sure there would be a market!! Knowing the exact usage of individual sockets within any house is clearly a worthwhile thing to do!

 

[ColJack]

so you'll know for the next house...
32A 4mm² radial to each room..

you can get plug in KWH meters.. a bit of epoxy to stop the students taking them out, and a clause in the rental agreement giving you monthly access to check them...

 

[dextrous]

so you'll know for the next house...
32A 4mm² radial to each room..

You're just so helpful at times

 

[electronicsuk]

Wish I had the cash to develop the system I'm talking about, as I'm sure there would be a market!! Knowing the exact usage of individual sockets within any house is clearly a worthwhile thing to do!

It's an interesting idea, and from an engineering perspective, constructing something that would fit inside a standard 2G socket shouldn't be all too difficult. However, it may be more difficult to couple data into the power line - it's not something I've ever dabbled with, but I believe it's done via superimposing a high frequency data carrier onto the line via transformers.

Still, you have to question if it would really be worth the cost - even if these were an off-the-shelf product, you can bet it would still be cheaper to rewire. It sounds as rewiring might be the best option anyway, as multiple bedsits running fan heaters plus other appliances on a single ring final is asking for trouble come winter.

 

[Chri5]

If you were to fit seperate circuits for each bed sit it would be easy.

You then buy however may "Owl" units you need on a 1 for 1 bed sit basis and since they are wireless you have no cable issues.

If you want to work via PC they do a USB unit that receives the wireless owl monitor signal, this would allow a print for tenant invoicing.

The only issues would be to:-

* Make sure each owl is on it's own wireless frequency (8 frequencies available so limited to 8 rooms)

* Clamp on the phase for the radial supply at a point where the clamp is secure and away from tampering minds

You could even tune the unit rate to allow the bill / tally cost to cover your 'service' charge such as cost recovery for radial provision and owl deployment.

http://www.theowl.com/index.php?page=about-owl

 

[dextrous]

[quote="electronicsuk";p="1286329Still, you have to question if it would really be worth the cost - even if these were an off-the-shelf product, you can bet it would still be cheaper to rewire. [/quote]

Not sure I agree. Let's say replacement sockets of the type I'm thinking of were £25 each, and guess 40 sockets plus a £300 receiver type thingy - comes to £1300. If it were possible to manufacture these "smart" sockets, then one could even incorporate a programmable limit for the available ampage availability per socket (thus allowing a bit more for a plug in oven or heater, and less for low usage outlets such as light, tv, pc's), which would enable one to ensure that excess current could not possibly be drawn from any given circuit with, say, a 32A rating.

Moreover, as we're not "live-in" landlords, it could be controlled and monitored via the internet using a bit of software.

A rewire, including replacement consumer unit/ card meters etc and using 4mm cable radials to take larger number of circuits, plus making good would no doubt cost more that this.

 

[Chri5]

Nice to be ignored

 

[bernardgreen]

This is a fairly simple device to design, But only by producing in large quantities could it manufactured as reasonably priced item. In almost all cases a re-wire would be more economical for rented property management.

That opinion is based on a design for a similar project but this design was not for the "domestic" market.

Thus a for a room with say 4 double sockets would provide 4 data feedbacks from which the total use of electricity could be logged, and the tenant charged pro rata accordingly.

The charging the cost is the difficult part as the system would have to be proven to be accurate to prevent overcharging by error.

The design mentioned measured and compared loads on circuits to detect street lighting equipment failures. Absolute accuracy was not necesary,.

 

[mattylad]

The device that you are after is quite possible, I know the guy who developed the Norweb control system that gave individual socket control
and communication over the mains. If it wasnt for his passing away last year I'm sure he could have developed it.

However, as has been said, go for a rewire.

 

[dextrous]

If you were to fit seperate circuits for each bed sit it would be easy.

You then buy however may "Owl" units you need on a 1 for 1 bed sit basis and since they are wireless you have no cable issues.

If you want to work via PC they do a USB unit that receives the wireless owl monitor signal, this would allow a print for tenant invoicing.

The only issues would be to:-

* Make sure each owl is on it's own wireless frequency (8 frequencies available so limited to 8 rooms)

* Clamp on the phase for the radial supply at a point where the clamp is secure and away from tampering minds

You could even tune the unit rate to allow the bill / tally cost to cover your 'service' charge such as cost recovery for radial provision and owl deployment.

http://www.theowl.com/index.php?page=about-owl

Many thanks for this idea. As you will have gathered I was thinking "outside the box" here and trying to avoid a rewire scenarion.