What would you do if water started coming through your ceiling? Or if an electrical appliance caught fire? These are the sorts of question that every householder – in fact, anyone who lives in a house or flat – should know the answer to. When urgent action is needed to avert a disaster, it is no use calling someone else – you need to move fast. But this is not the sort of knowledge you learn at school.
Which is where this web page comes in.
I’ve been doing domestic electrical and plumbing work for longer than I care to remember – usually for myself or for family and friends – and have been quite astonished to discover how many people do not know where their stopcock or their main electrical switch are located. So I thought it might be a good idea to share some of the basics.
The water supply coming into a residential property (house or flat) is controlled by one or more stopcocks. These look like ordinary taps, except that they are usually made of brass and have a pipe coming out each side rather than a spout; they work the same way – clockwise for off, anticlockwise for on. The most likely place for your main stopcock is near the front door, where the cold water pipe enters the property. Have a look for it at a time when no-one (including the washing machine) is using any water; try turning it off (it may be rather stiff) and check that all the cold taps go off. If any don’t, there may be another stopcock somewhere.
NOTE: After turning a stopcock off and on, it may leak slightly from the point where the spindle enters the body of the tap. Sometimes this stops on its own; sometimes it will require the gland nut (through which the spindle passes) to be tightened (but if you do this, check that the tap can still be turned,as it will become harder). If the leaking can’t be stopped, you may need to get the stopcock replaced (they are fairly cheap, but sadly labour isn’t).
Some cold water taps (particularly in bathrooms) may be fed from a cold water storage tank rather than the mains. You can tell if this is the case if (a) none of the stopcocks in the house seem to affect the taps in question; (b) the pressure may be a bit lower than in the kitchen tap, which is normally mains-fed; (c) after running the tap for a while you may hear a tank filling up somewhere.
Taps fed from a cold water tank, and hot water taps (if fed from a tank) are isolated by means of gate valves. These look a bit like stopcocks but have a wheel (often brightly painted) instead of a normal tap handle. Again, clockwise to turn off, anticlockwise to turn on.
If you can’t turn the water off after trying all of the above, or if the leak is from a neighbouring property, there is always the last resort – the stopcock in the pavement outside. This will be under a hinged metal lid about 10-15 cm square. It is basically another stopcock, but may be difficult to turn. It may even be under a layer of soil. For difficult cases, there are special tools which hook over the tap handle and are turned by turning a much larger handle at the other end of a metre-long spindle.
Central heating systems nowadays come in two basic types. One is the more traditional open system which is fed by a header tank; the other is the sort of sealed, pressurised system associated with modern “combi” boilers.
If water is leaking from a radiator or a central heating pipe, it will not leak forever if you have already turned off the mains supply. However, if you cannot control the leak by using a receptacle and/or turning off the radiator valves, you may need to drain the system. Every central heating system will have one or more drain cocks fitted (usually at the lowest point). These consist of a serrated spout onto which a hosepipe can be pushed, and a spindle which is square in cross-section and can be turned by a pair of pliers or a suitably-sized spanner. (NB Turn the heating off before draining it!)
Pressurising Central Heating Systems
Many modern central heating systems incorporate a “combi” boiler which does both heating and domestic hot water without the need for tanks. The water in these systems is sealed in and pressurised (unlike more traditional systems where there is a header tank open to the atmosphere); however, over time, water is gradually lost, even from sealed systems, and the pressure drops; the system must be re-pressurised from the mains or it will stop working. Unfortunately, when these boilers were first introduced, the water authorities were understandably unhappy about having dirty central heating water connected into the mains – under normal circumstances this will not pollute the mains, but there are times when the water could flow the other way. So the filling pipe, which runs between a heating pipe and the main cold water input to the boiler, often looks like an afterthought, and may even be disconnected. It is usually a flexible pipe. Re-pressurising is a simple matter of turning the heating off and then opening the valves at each end of this pipe, while keeping an eye on the pressure gauge on the boiler – if this is a digital display, the boiler manual will tell you the required pressure; if it is an analogue one (aka a dial!) it will have a green region showing permitted pressures.
Don’t forget to turn the valves off afterwards!
Some modern boilers may have a filling loop already incorporated, and instructions in the manual on how to operate it, suggesting that the regulations may have changed, or perhaps they are just hoping no-one will notice.
Doing this yourself is a lot cheaper than getting a plumber in to do it! In case you are not sure whether your boiler is a combi, the gas version will have at least five pipes coming out of the bottom, and they also have a pressure gauge.
Hot Water Tanks
If water is leaking from a hot water tank, you may need to drain the tank. Hot water tanks are cylindrical in shape with a rounded top (and are usually referred to as “cylinders”). They are made of copper, but are often clad in thick polystyrene lagging. Some have a built-in cold storage tank at the top (this sort is known as a Fortic tank). A hot tank will always have a drain cock at the bottom. Proceed in exactly the same way as for draining a central heating system. (NB If you have an electrical immersion heater, you will need to turn this off before draining the tank).
If you want to avoid blocked drains (and unblocking a drain can be expensive, particularly if you do not have inspection covers in the right places) you should take care to control what goes into them. Drains that empty into a hopper or open gulley on the outside of the house can become blocked with leaves or other debris; check them regularly. Try not to flush too much solid matter down the kitchen sink; and when you wash your hair, use a filter in the plughole to catch any loose hairs in the water. There are powerful drain cleaning agents available, such as D-Block (which is very strong acid – handle with care!) and it is always worth trying such things before calling a plumber.
If water drains away slowly from a sink, bath or basin, you can try using a plunger, which can be bought fairly cheaply from a hardware shop. All these drains include an S or U shaped pipe which is permanently filled with water; this prevents smells from the drain from getting into the house. However, solid matter can accumulate in the U-bend and eventually block the drain. A plunger, which is a rubber hemisphere connected to a wooden handle, will usually shift such material. However, remember that most sinks, baths and basins have an overflow which is connected to the drain above the U-bend, so that plunging the outlet with the overflow uncovered will do virtually nothing. You will need to cover the overflow with your hand to get a decent amount of suction or compression.
If an overflow pipe is discharging water it is a sign that something needs doing. Specifically, it is telling you that the ball valve, which controls the flow of water into a tank or cistern, is not working properly. These valves are supposed to shut off when the water in the tank reaches a certain level; however, if the washer in a ball valve wears out, the tank will continue to fill (slowly at first) and the level will rise to the point where it starts to come out of the overflow pipe.
If it starts to do this you need to act now – not next month or next year. The washer will gradually deteriorate, and the flow of water through the overflow pipe will increase. Eventually it will reach a point where the overflow pipe can no longer cope with the water and the level will rise to the rim of the tank and start to spill over the edge, damaging floors, upholstery, carpets, ceilings etc.
Taps, too, have washers which wear out and need replacing. If you find that you have to keep winding the tap down harder and harder to turn it off, again, act now. If you don’t, there may come a point where the housing that holds the washer will part company with the part of the mechanism connected to the spindle. This may result in the tap being either fully on or fully off all the time, with predictable results!
If you live in a basement flat with a suspended wooden floor, it is important that air can circulate in the space under the floor, or it will get damp and the floor will rot. This is achieved by means of air bricks, which can be seen on the outside of the hosue, just above the ground.
Check that your air bricks are not blocked or covered up. If you have a loose floorboard, it is a good idea to have a look under the floor and check that it is not damp. If it is, get help before the rot sets in!
If you smell gas, and you can’t find where it is coming from (such as a gas hob, oven or fire that has gone out) immediately, you should turn off the main supply, open windows, contact your gas supplier and leave the property. So it is important to know where your main gas cock is and that you are able to operate it in an emergency. A gas cock is normally a lever which can turn through 90 degrees, and it will be located next to your gas meter – normally near the entrance to the house or flat, or in a plastic enclosure outside. If you have one of these, it will need a special triangular “key” to open it – make sure you have one of these and that it works.
You may be tempted to try turning the gas off, just to check that you are able to; if so, STOP! Gas is not the same as water. If you turn the main gas cock off and on again, any appliances that were alight will not re-light (with the possible exception of some modern boilers – but don’t assume any will). So if you are going to test the gas cock, you need to first make sure that all your appliances are off, and that if any of them have pilot lights, you know how to re-light them. And if there is any possibility that the gas cock is not yours but a neighbour’s, you must talk to your neighbour before turning off, and conduct the test jointly with him or her.
Electricity presents two quite separate hazards, but many people are confused about these and mix them up. First, some basics:
Electricity is basically the movement of electric charge through a conductor such as a wire or appliance. The current is the rate at which charge is flowing. In order for any current to flow at all, there must be a complete circuit from one of the terminals of the power supply (battery, mains, solar cell etc) to the other. The voltage is the “pressure” which is pushing the current round the circuit.
Hazards of Electricity (1): Fire
When an electric current flows, it produces heat. The higher the current, the more heat. And the amount of heat produced by a given current also depends on the electrical resistance of the circuit. The resistance of a wire, in turn, is higher for thin wires and lower for thick ones.
If too much heat is produced, it can be dangerous and may even cause fires. So electrical appliances are designed to limit the heat produced under normal working conditions to a safe level; and domestic wiring systems are also designed so as to limit the heat produced by limiting currents to safe levels. This is done by using appropriate cable sizes for the various sockets, lights and other appliances in a house or flat. The cables are connected to the supply via fuses or circuit breakers which blow or “trip” if too much current flows. These fuses or circuit breakers are housed in a fuse box or consumer unit.
Electrical appliances take various sizes of current depending on their function. Current is measured in amps. Most light bulbs use a fraction of an amp; electronic devices also use low currents, although for a large appliance such as a computer this may be an amp or two. Appliances with motors in them (such as vacuum cleaners) may use several amps; but the highest users of electricity are, as you would expect, those appliances which take advantage of the heating effect: kettles, hair dryers, heaters. Plug-in appliances have a fuse in their plug which protects the appliance and flex from overheating; these fuses are commonly available in two sizes – 13 amp (brown) for kettles, hair dryers etc, and 3 amp (red) for lamps and small electronic appliances. There are also 5 amp fuses but they are not so easy to get. If in doubt, look at the label. All appliances have a wattage rating on them; the wattage is basically the volts times the amps. So, for example, if you have an appliance rated at 500 watts, since the mains voltage is about 240 volts, the current will be 500/240 or about 2 amps; so a 3 amp fuse should suffice.
In the fixed domestic wiring system, cable sizes vary according to what they will be used for; a given cable has a maximum safe current as defined by the IEE wiring regulations, and each cable will be protected by a suitable fuse or circuit breaker in the consumer unit.
Fuses and Circuit Breakers
Circuit breakers are basically more modern versions of fuses. In a fuse, there is a small piece of wire which will melt if the current is too high, breaking the circuit. In a circuit breaker there is a current sensor which operates a switch if the current gets too high. So fuses have to be mended with new wire, or replaced with new fuses (if they are of the non-repairable cartridge type) but circuit breakers just need resetting – the switch has to be manually returned to the “on” position. (NB Circuit breakers are much more sensitive than fuses – sometimes too sensitive. It is not uncommon for a 6 amp circuit breaker to trip as a result of a light bulb blowing. Replace the bulb and reset the breaker.)
In your consumer unit, the various fuses or circuit breakers should be labelled to tell you what they are connected to; but often they’re not, so another useful little exercise is to methodically go through the unit, removing fuses or switching off circuit breakers, and checking what has gone off; then labelling them so that if you need to turn something off quickly in future, you will know which one. (Make sure everything is initially off before you start this exercise though – turning the mains off when someone is using a computer will not win you many friends!) Sockets are usually connected in a ring main which will normally have a 30 amp fuse or 32 amp breaker; lighting circuits are normally separate and are protected by a 5 amp fuse or 6 amp breaker; fixed appliances such as immersion heaters normally have their own fuse (15 amp) or circuit breaker (16 amp). Showers can be very heavy consumers of electricity, and may require a 40 or 50 amp fuse or breaker.
If you do decide to mend a blown fuse from your consumer unit, make sure you use the right sort of fuse wire. The fuses are marked with their rated currents and also colour coded (red for 30 amp fuses used for sockets; white for 5 amp fuses used for lighting; blue for 15 amps, usually used for circuits that feed only one appliance such as an immersion heater). The fuse wire is secured by two small screws and passes through a heat-proof channel with an “inspection window” allowing you to check visually if it is OK. (Some fuses incorporate a large cartridge type fuse – like the one that goes in a plug, but bigger – rather than fuse wire).
Safety Tips for Fire Prevention
A properly installed domestic wiring system should not present any hazards. You can help reduce risk by minimising the number of plugs and sockets between an appliance and the supply, since these are points at which you may get bad connections, with higher than usual resistance and correspondingly more heat produced. Heavy appliances such as heaters and washing machines should be plugged directly into a fixed socket. If you must use an extension lead, make sure it is suitably rated – many extension leads have thin cable and should only be used for low-current appliances. (Note also that the maximum safe current of a coiled extension lead will be lower if it is still coiled up, as the heat cannot escape properly). Try to avoid the sort of adaptor that allows several appliances to be plugged into a single socket, especially if the appliances draw large currents. The main fuse will not blow until the current reaches 30 amps (and even then, not immediately); but having such a current flowing through the prongs of a single plug (which may not be making very good contact anyway, especially if it has heavy cables pulling it to one side) is not a good idea.
Hazards of Electricity (2): Electric Shock
The other problem with electricity of course is that contact between a human body and a mains voltage electricity supply will produce a nasty shock and can even kill you. The currents required to do this are much, much smaller than the sort we have discussed so far. In fact a mere twenty-fifth of an amp can kill you. So fuses won’t help you here.
Again, a current will only flow if there is a complete circuit. So, in theory, if you touched the live wire while every other bit of you was well insulated from earth, you might be all right – but don’t try that at home!
Here’s a bit more terminology. I mentioned “the live wire” just now – but what does that mean? Well, the two wires that carry current to and from an appliance are called the live (L) and neutral (N) wires. The earth is a pretty good conductor of electricity, and the neutral wire is connected to earth at the sub-station. So touching the live wire whilst standing on wet soil in bare feet is not a good idea, because a current can flow from the live wire, through you, to the earth, and hence back to the neutral wire at the other end, making a circuit.
Any exposed metal parts in an electrical appliance must, according to the regulations, be connected to the earth wire, which in turn is connected to the earth locally. Then, if there is a malfunction in the appliance and these metal parts become live, it will immediately blow the fuse – hopefully before you get a chance to touch it! Many appliances are designed in such a way that there are no exposed metal parts, making them intrinsically safer, but of course you can’t do this with a washing machine or cooker.
As an extra precaution, some consumer units – especially the modern type with circuit breakers – are fitted with a Residual Current Device (RCD) – sometimes known as a Residual Current Circuit Breaker (RCCB) or Earth Leakage Circuit Breaker (ELCB). These devices check whether there is an imbalance between the live and neutral wires, and if such an imbalance is detected, they switch off the supply. The theory here is that if more current is flowing in the live than the neutral, this extra currernt is flowing to earth, and may be going through your body; at any rate, wherever it is going it is not right. You can tell whether your consumer unit has one of these (it normally replaces the main switch, on the right hand side of the unit) because it will be labelled appropriately and will incorporate a test button which simulates a fault and switches the supply off. This test button is another thing you can try out – but remember to switch computers etc off first!