Should immersion heater be on RCD?

Asked By: Larosi Landais | Last Updated: 22nd April, 2020
Category: home and garden home appliances
4.3/5 (298 Views . 21 Votes)
As you've been told, the immersion heater does not need to have RCD protection (unless it's in a bathroom - and, even then, probably not if it were 'in a cupboard').

Click to see full answer


Consequently, does a water heater need RCD protection?

As far as I'm aware there is no requirement for rcd protection for water heaters, although you are obviously governed by the regs regarding cable buried in walls etc.

Furthermore, what is the resistance of a 3kw immersion heater? The resistance of a 3kw immersion heater should be approximately 20 ohms. If the resistance is infinite, you know it has burnt out.

Beside above, what MCB size would an immersion heater require?

It is OK to use 13A or 16A timers on a 20A MCB immersion circuit - assuming that the immersion load is within the timer's current carrying capacity.

How do you install an instantaneous water heater?

How to Install an Instant Hot Water Heater

  1. Locate an area for the new hot water heater.
  2. Hold the hot water heater against the desired wall.
  3. Turn off the water supply to the nearby sink by hand-turning the valve.
  4. Cut the cold water supply line with tube cutters close to the heater's installation area.

14 Related Question Answers Found

How many amps does an immersion heater use?

stevehayes. just a quick question-a 3kw immersion heater at 240 volts will use 12.5 amps - so will a 13amp fuse be sufficient in the spur socket?

Do immersion heaters use a lot of electricity?

The cost of electricity is about 14p/kWh, which means that it would cost about 45p to run a 3kW immersion heater for an hour. Normally though, the immersion will turn on and off via the thermostat so the amount of time they are on fluctuates, depending on the existing temperature of the water in the hot water tank.

Why do immersion heaters fail?

Failure of immersion heater elementsin a normally operating copper hot water storage tank may be caused by corrosion, or by development of an electrical defect. Frequent element failures at regular intervals occur in relatively few premises and these have particularly saline and/or scale forming water supplies.

Is it safe to leave immersion heater on?

It's best to leave your immersion heater on 24 hours a day. Myth or Truth? MYTH. It's always best to place the water heating on a timer, as the energy lost from a hot water tank depends on the temperature difference between the surface of the tank and its surroundings.

Is my immersion heater on?


How do I know if my electric immersion is on? The first thing to do is follow the wire (where possible) from the immersion heater element at the top of the hot water tank to the wall, where hopefully you will see a switch. If it is on, flick it off! If you can't see any wires, then the process is a bit trickier.

Can you adjust the temperature on an immersion heater?

Isolate the immersion heater from its power supply before removing the cover. If necessary adjust the control thermostat setting by turning the dial with a screwdriver blade until the arrow points to the desired temperature.

Can an immersion heater explode?

If the temperature is set too high or the pressure relief valve of a water heater malfunctions, a water heater can explode. This can happen with a gas or electric hot water heater. Although it is unlikely for water heaters to explode, when they do, they operate much the same as a rocket.

What is the ideal temperature for an immersion heater?

The hot water cylinder thermostat controls the temperature of water that comes out of the taps. In “hard water” areas it is recommended that the thermostat on the immersion heater is set to 50°C. If you have a twin immersion heater the top element should be set to 50°C and the lower one to 60°C.