Short answer
Yes: Regulation 36 of the Electricity Regulations 1994 requires an RCD that trips at 10mA or less in wet locations such as bathrooms, and ST has required it for water heaters since 2014. With us, fitting a heater on an existing point costs RM150 – RM250, and a new point with a 10mA RCCB costs RM350 – RM550.
What do Malaysian rules say about water heater RCCBs?
Regulation 36 of the Electricity Regulations 1994 sets the sensitivity of residual current devices (RCDs) by location: 10mA or less for wet locations, 30mA or less for socket circuits and hand-held equipment, and 100mA or less for general protection. A bathroom with a shower is the textbook wet location.
In 2014, Suruhanjaya Tenaga made 10mA RCD protection a requirement for water heaters. Wet skin lets far more current flow at the same voltage, so the shower gets the most sensitive protection. Every new water heater point we install has its own 10mA RCCB, separate from the RCCB in your DB box.
What is the difference between 10mA, 30mA and 100mA RCCBs?
The mA rating is the leakage current at which the RCCB trips; the lower the number, the more sensitive it is. 30mA is the level chosen to protect people from fatal shock in normal, dry conditions. 10mA adds a safety margin for wet conditions, and 100mA is mainly there to catch earth faults that could start a fire.
Many older houses have a single 100mA RCCB for the whole house. That helps against fire, but it does not reliably protect a person from shock. If your board is like this, adding a 30mA RCCB for the socket circuits and a 10mA RCCB for the water heater is a worthwhile upgrade.
| Rating | Where it is used | What it protects against |
|---|---|---|
| 10mA | Water heaters, bathrooms and other wet locations | Shock to a person in wet conditions |
| 30mA | Socket circuits, hand-held appliances, most home DB boxes | Shock to a person in normal conditions |
| 100mA | General protection for the whole installation | Earth faults and fire risk, not personal shock |
Is the ELCB built into my water heater enough?
Most instant water heaters sold in Malaysia have a built-in ELCB with its own test button on the unit. It is a useful extra layer, but it only protects from the heater onwards. The cable, switch and connections between your DB box and the heater are not covered by it, and it sits inside a hot, humid casing.
A separate 10mA RCCB, at the DB box or next to the heater's isolator, protects the whole circuit and can be tested and replaced on its own. That is why we fit one even when the heater has a built-in ELCB. Press both test buttons once a month to check they trip.
Why does my house trip when I turn on the shower?
If the RCCB trips only when the heater is on or hot water is running, the heating element is the usual suspect. As elements age, small cracks let current leak into the water and to earth. The 10mA RCCB catches this first, which is exactly its job. Switch the heater off at its isolator and stop using it until it is checked.
A tingle from any tap, shower head or heater casing needs action straight away. Switch off the heater at the isolator, and at the main switch if needed, keep everyone out of the bathroom and call an electrician. Do not use the shower again until the fault has been found.
- Tripping only when the heater is on or hot water flows
- The heater's own ELCB trips repeatedly
- A slight tingle from the shower head, tap or heater casing
- Water leaking from the heater body or cable entry
- Water stays lukewarm even on the highest setting
- Burn marks or a smell around the heater switch
How much does water heater installation cost?
Fitting a new heater on an existing, correctly protected point is a quick job. A new point costs more because it needs a dedicated cable from the DB box, a 20A double-pole switch outside the shower area and the 10mA RCCB. Prices below include labour and materials, with the heater supplied by you.
If your existing point has no 10mA RCCB, we will recommend adding one before connecting the new heater. In some older condos, the heater shares a circuit with the bathroom lights or sockets; it should be moved onto its own breaker, since most instant heaters draw 15–16A on their own.
| Job | Market range | My Power Care KL |
|---|---|---|
| Water heater installation (existing point) | RM80 – RM250 | RM150 – RM250 |
| Water heater with new point + 10mA RCCB | RM200 – RM600 | RM350 – RM550 |
| RCCB / ELCB replacement | RM140 – RM600 | RM250 – RM450 |
| Power tripping: find and fix | RM100 – RM400 | RM150 – RM400 |
How do you keep a water heater safe?
Water and electricity are a bad mix in a small tiled room, but a properly installed heater is very safe. Most of the dangerous cases we come across involve a missing or bypassed RCCB, a DIY connection, or a heater that kept tripping and was rewired to stop it. These habits keep the risk low.
- Give the heater its own circuit and a 10mA RCCB
- Keep the switch or isolator outside the shower area
- Press the RCCB and heater test buttons once a month
- Never bypass or remove an RCCB that keeps tripping
- Replace heaters with cracked casings or water leaks
- Have new points and replacements installed and tested by an electrician