immersion heater and a shower pump

[terminator]

Yep, that is what i thought - not exactly an example of joined up thinking

Regs say immersion can be on double pole FCU with a 13A fuse, but not on a plug top with a 13A fuse. Take the plug out and you have DP isolation .

Be nice if they gave the occasional reason why.

Probably because the plug can be inserted or withdrawn from an unswitched socked thereby causing arcing!

 

[pushrod]

thanks telectrix for your fast help.any ideas to keep the water hot?or is this just the way things are for this smallish sized heater?would putting extra insulation really make alot of difference?thanks

Putting extra insulation on a hot water tank will help keep the water warmer for longer but not indefinitely as heat will always escape through the various copper pipes. In my own house the hot water tank is in the cupboard with the towels so i don't mind some heat escaping as it warms them. It is very hard to keep the water vastly hotter than its surroundings. Only you can really decide if it is worth spending money to keep the water warmer for an extra hour or two.

Probably because the plug can be inserted or withdrawn from an unswitched socked thereby causing arcing!

But you can switch the socket off before the plug is withdrawn and it is very unlikely that it is going to be regularly removed anyway. Household appliances used on unswitched sockets are going to be much more of a problem in this regard.

 

[terminator]

But you can switch the socket off before the plug is withdrawn and it is very unlikely that it is going to be regularly removed anyway. Household appliances used on unswitched sockets are going to be much more of a problem in this regard.

Yeah I agree Pushrod, but I was just trying to think of their reasoning behind the ambigous regs. How many householders bother to switch off before removing plug and it's a fairly heavy load. It wouldn't take too long to burn the socket/plug if it was done regularly. I know you say that's unlikely, but expect the unexpected with the uninitiated.

 

[pushrod]

Yeah I agree Pushrod, but I was just trying to think of their reasoning behind the ambigous regs. How many householders bother to switch off before removing plug and it's a fairly heavy load. It wouldn't take too long to burn the socket/plug if it was done regularly. I know you say that's unlikely, but expect the unexpected with the uninitiated.

Maybe that is a friday afternoon reg, after they had all been to the pub

 

[malcolmsanford]

hi all,i'm new to this and don't know if this is the best place to ask my question?i have an immersion heater,the whole house is electric.i have storage heating on e7 tariff,and want to know if i can have a timer fitted to my immersion heater to make the most of this.it is currently wired directly into the wall,no plug socket,and simply says on or off.is this an electrician or plumber job?and can it be done?also the immersion heater is not huge,and has one jacket to insulate.if i heated my water in the morning,it'd be lukewarm by the time i need to wash up and bath my kids in the evening,as this has happened before.but if i heat it an hour before i need it,its hot (although even if i use the whole tank of hot water just to myself for a hot bath it still doesnt have enough to fill up or top it up)is insulation the problem?and the fact the tank isnt huge?i take it i cant boost as i only have one pre programmed thermostat.i dont want to have to keep heating at peak tariff to get nice hot water :-( its a rented house,so cannot change this setup.please help,thanks in advance.

Can't see how a timer is going to help you really. Even if you fit it and it comes on in line with your storage heaters, the circuit to the immersion heater is still going to be on connected to your normal tariff.

If you have an older E7 system it will have 2 meters and 2 fuse boards. I meter and board for your normal electrics say which the immersion is on, and another meter and board for your heaters.

If it's a modern system then it will most likley have a single meter but with 4 large cables coming out of it to either again 2 fuse boards, or a single fuse board split in normal and E7 system.

If you do decide to fit the immersion into the E7 system you have to remember that by the time you get home in the evening there will be very little hot water as it's charges up all night and remained hot during the day, slowly cooling down.

It may pay you to look at either setting up the existing system on a timer which is better for you, say coming on at 5am going off at 8am, then coming on again at 4pm and going off at 7pm

Or you can get a tank installed that as 2 elements which would utilised the E7 on one element and the other element the normal electricity.

Whatever you decide it will pay you to get an electrician in to see what is the best path for you.

 

[tonys]

An immersion heater on a plug top - not allowed as should be on a switched connection unit to BS 1363-4. What code would you give it ? and out of interest what is the thinking in not allowing it as a plug and socket would give double pole isolation?
cheers.

Where exactly does this information come from ?

 

[SimpleSimon]

Yeah I agree Pushrod, but I was just trying to think of their reasoning behind the ambigous regs. How many householders bother to switch off before removing plug and it's a fairly heavy load. It wouldn't take too long to burn the socket/plug if it was done regularly. I know you say that's unlikely, but expect the unexpected with the uninitiated.

The only reasoning I can think is with a plug and socket the householder than has the chance to put one of those double plug top and have both the immersion heater and some other big appliance on the same circuit. Possible overload.

But the reasoning goes out of the window because immersion spurs are usually located in an airing cupboard so what else you would fit in an airing cupboard I don't know.

 

[Deleted member 9648]

I suspect the reason is that most 13a plugs and sockets dont handle prolonged periods at maximum load very well. I've seen plenty of burnt out 13a sockets in airing cupboards....often with piles of clothes stacked round them.

 

[malcolmsanford]

Problem with putting a 3kw load onto a BS 1363 Socket is the load on the socket outlet not the circuit. Very few sockets today are designed to take a 3kw load on the socket and plug top, MK and Crabtree still might, but the majiority of them are rated at about 8-10amps,

A lot of people get the not allowed bit from appendix 15 where they mistake not supplying from the ring final circuit to mean a BS 1363 Socket. Because it is a large load if it was connected to a ring it might deem to unbalance it.

Though a BS 1363 socket outlet affords you on load isolation and functional switching the same as a BS 1363-4 FCU very few sockets are double pole as the FCU normally is, and you have the loading situation as I stated above.

IMO I would not connected a 3kw load with a plug and socket.

 

[andyb]

Where exactly does this information come from ?

554.3.3 Tony