Device that cuts power if too much is used for a long time

[ringi]

Is there a device that cuts power if too much is used for a length of time?

I wish to have some letting room’s setup, so tenants can use a kettle or hair dryer, but not an electric fire.

Is there a reasonably priced device that will cut out when too much power is used over a length of time, but allows a lot more to be used for a few minutes?

 

[topper harley]

Why would you want to do this?

Is for financial reasons?
Is it from a 'load' point of view?
Is it for a fire safety reason?

I think you will have some unhappy tenants if you deliberately remove all electricity from their home if they use 'too much power for too long'.

I think you need to explain the reason so you can be provided with the best solution.


regards

 

[PrenticeBoyofDerry]

Will they be allowed to have lighting? If so, remove the fire blank of all sockets to habitable areas and tell them to warm their hands on the lamps!

As a landlord, you have a duty of care to your tenants, supplying them with a means to eat and drink and keep warm, I would think would be the minimum of that requirement.

 

[leeco]

Best thing to do is don't let them have any power. Make them freeze.

 

[bernardgreen]

Is there a device that cuts power if too much is used for a length of time?

Yes It is called a pre-payment meter.

But your duty of care to tenants requires some provision to prevent harm if or when the power is cut.

 

[Steve]

I understand what the OP is suggesting. He wants to set up a HMO with central communal heating and restrict the power useage of the tenants so they don't go supplementing the heating with expensive electric heating, or setting up a cannabis farm.

I don't think there is a device that will do what you suggest, without a complex circuit involving some kind of programming device, current sensing and relays.

 

[ringi]

I will be renting out a HMO (e.g. a properly when the tenants each rent 1 room and the landlord pays all bills, with a shared kitchen).

There will be gas central heating on a timer and a thermostat that is locked, so each tenant can turn down the heat in their room with the TRV, but can’t turn up the heating too much.

There are far too many cases of tenants in HMO turning the heating up as much as possible and just opening the windows to control the temperature. This includes tenants buying fan heaters.

I can control heat usage on the CH side with ease, while not restricting the tenants too much. (It is not hard to interlock the CH in a room with a window sensor.)

I wish to have a way that I can stop them buying their own electric heaters without stopping them using hair dryers. This is both to control power usage (e.g. cost to me) and for safety as there have been too many fires with tenants buying electric heaters then putting cloths etc over them.

It is becoming common for landlords to put each room on its own 5 amp RCCB, often with a 2nd circuit for lighting, so the lights don’t fail when the socket’s RCCB trips. The tenants are then just told that if they wish to use a hair dryer they must use it in the shared kitchen – I don’t like this solution!

So I want a RCCB that allows 5amp for ever but will allow 20amp for say no more than 20 minutes every hour.

 

[securespark]

If you were to run 20A off a 6A RCBO, how long would it be before it tripped?

 

[ringi]

If you were to run 20A off a 6A RCBO, how long would it be before it tripped?

I hope a normal RCBO would trip very quickly if a load of over 3 times its rating! (But I don’t have the response curves in front of me)

Also I don’t think it is a good idea to do a design that only works due to a limitation in a device; the next version of the device may not have such a big limitation.

 

[Steve]

How would you interlock the heating in an individual room? The window sensor is a good idea (I recently saw this in Cyprus where reed switches operated 20A contactors to knock off the air con in our hotel room), but would you knock off the whole system? Alternatively you could have a 2 way valve for each room (which you could also wire to a room stat which are more accurate than TRVs).

5A MCB is a good idea, but could lead to your tenants getting cross with the design of the installation and taking matters into their own hands . . . One shop I worked in had a 6A MCB protecting 2 EPOS checkouts and a server as well as all the networking equipment and wifi APs. I was told this was for protection. But the MCB frequently tripped after a power cut due to the startup surge.

 

[ringi]

How would you interlock the heating in an individual room? The window sensor is a good idea (I recently saw this in Cyprus where reed switches operated 20A contactors to knock off the air con in our hotel room), but would you knock off the whole system? Alternatively you could have a 2 way valve for each room (which you could also wire to a room stat which are more accurate than TRVs).

There are “smart” TVRs about, that can connect wirelessly to window switches and also allow timing control to be programmed by each room user.

TVRs are more accurate then room stats with 2 way valves, as a TVR will reduce the flow rate, but a room stat will just turn the heating off until the room gets too code. Anyone sitting next to a radiator would prefer a radiator was always warm rather then hot for 5 minutes then cold for 10 minutes.

Top end UFH heating control systems also modulate the flow of water and can be used with radiators.

 

[Steve]

Actually T R Vs cycle the radiator on and off but the time between on and off cycles is usually not very long because the TRV senses the heat from the pipe itself and starts the off cycle soon after the rad has turned on, and similarly starts the on cycle soon after turning off. Hence the rads usually don't fully cool. I find my TRVs hard to control, but maybe thats because I got cheap ones.

The fact they sense the heat from the rad itself to me is like having a room stat mounted above a rad. This is why I prefer room stat and 2 way valve (or smart TRV is you eluded to)

 

[paulc2]

I think you need to either find a way of billing them fairly for the power they use, or adjusting the rent to take into account potential electricity usage. Its going to be simpler in the long run, and fairer for both sides. Trying to tell them what they can/can't do it overly restrictive and I think you could open yourself to a legitimate complaint(s).

 

[paulc2]

For example, if you can get their electricity sockets/lighting etc onto discrete circuit(s), you could install one of these into the consumer unit or a separate box:

http://www.allaboutelectrics.co.uk/100a-2-module-kwh-meter.html

 

[ringi]

Actually T R Vs cycle the radiator on and off but the time between on and off cycles is usually not very long because the TRV senses the heat from the pipe itself and starts the off cycle soon after the rad has turned on, and similarly starts the on cycle soon after turning off. Hence the rads usually don't fully cool. I find my TRVs hard to control, but maybe thats because I got cheap ones.

The fact they sense the heat from the rad itself to me is like having a room stat mounted above a rad. This is why I prefer room stat and 2 way valve (or smart TRV is you eluded to)

Some SmartTRV have the option of a remove stat, most have a stat build in. If the radiators are connected at the bottom, then heat from the radiator will not have much effect on a TRV. You can also get a ‘cable’ that lets you mount the TRV head remove from the radiator.

Normal TRV can be hard to adjust as you cannot hear them “click on”, my wife always turn them too much rather then making a very small change then waiting an hour to see if it is enough. (Way can’t there be two buttons marked “I am too hot” and “I am too cold”)

Also if you have a fixed speed pump, as the TRV closes down the pump will increase the pressure differential so the TRV may not be able to reduce the flow of water without having to completely shut.

(The Drayton TRV4 is a manual TRV that has a liquid sensor rather than expanding wax, so works a lot better than some cheaper TRVs Our Drayton TRV4s don’t cycle. The very old TRV with bimetal strips on some of our radiators do cycle.)

Smart TRVs have been created by a few companies to allow zoning of a CH system without having to change any of the pipe work, add a modulating pump and a boiler that has a wide modulating range and you can get a very adaptable system. (A buffer tank may be needed to stop the boiler cycling if it can’t modulate low enough.)

(I first found out about smart TRV when I was thinking about zoning our large bungalow, there is no clear way to divide it up into zooms as rooms can change function with ease.)