Fishy smell in Airing Cupboard. Electrical Problems?

1) What is the cause of a fishy smell?

The fishy smell occurs when plastics, PVC and cable insulation begin to overheat and melt. If left unattended the result is like the picture above. Plastics give off a fishy odour when they burn and it is a sign that the electrical system is in distress. 

2) Why do immersion switches burn out?

Electric heating elements in an immersion tank are VERY powerful and as a result they demand a lot of electrical current. Incorrect switches are commonly installed for this purpose and as a result, they overheat under the electrical demand and burn out or catch fire. 

It is vital that you have your immersion switch checked if it is the same type as pictured above. An electrical heating element cannot be installed on a 13 amp fused spur switch as is commonly the case. If so, the switch will eventually overheat and the result can be very serious indeed.

3) Immersion Elements

It's not just the electrical connections and incorrect switches that can be affected with immersion element circuits. The actual immersion element connections can become loose and burn out. If you detect a fishy odor in the water tank cupboard then turn the power off and remove the immersion connection cover to visually inspect the terminals. 

4) What about fish smells from the shower?

Just as with the airing cupboard. If you can smell a fishy smell from the electric shower then this needs investigating as soon as possible. 

Electrical Shower circuits are very power hungry circuits that demand a lot of electrical current from the consumer unit or fuse box in your home. Combine this with the fact that many showers are incorrectly installed and are too powerful for the supply and we have a recipe for disaster!

(The rear of a shower switch)

We can see from the photograph above that the shower switch here has burnt out. This has happened as a result of loose electrical wiring. Electrical wires are required to be tight and when they work loose like this, they will burn out. The photograph below shows a shower pull cord switch that had been poorly wired and resulted in the same fate.

(Poor wiring on a shower pull cord switch)

5) Fishy Smells from the fuse box cupboard?

A picture paints a thousand words, so here is another one of our delightful finds. This fuse box had suffered decades of neglect and required some TLC which it never received. As a result, it gave up working due to burn out at the MOST INCONVENIENT time possible.

We can see that the circuit breaker / fuse carriers here have burnt out and the highest rated has suffered complete destruction along with the wiring for the circuit. This was unrepairable and due to the age of the wiring in the property a rewire was recommended.

The owner reported a faint strange smell. The source of the smell was discovered when the cupboard was opened and the fuse box cover removed. The plastic smell is unmistakable, burning plastic components give off a very bad smell indeed. 

6) Fishy Smell Elsewhere

If you detect a fish smell ANYWHERE in your home then it is likely to be electrical components, circuit breakers or electrical appliances that are suffering physical damage from overheating. Try and narrow down the problem as quickly as possible as any delay could lead to electrical fire.

7) Where is the fish odor coming from?

Electrical systems contain many wiring junctions which are a weak point in the circuit. Wherever a junction is made, we rely on connections to stand firm and stay tight. Whilst it is poor practice and even outlawed in some countries, wiring junctions can exist in the crawl space under your home, behind kitchen cabinets or in other inaccessible places.

Where junctions like this exist, they should be constructed such that they require no maintenance. Many of them are not installed this way and as a result, their connections are nearly impossible to reach to check for tightness or signs of damage. 

The rotten smell that comes from burning electrics can leak through anywhere into your home making it hard to pin the burning smell location down to a specific place. 

8) Are all electrics at risk?

To an extent, all electrical circuits can suffer from the same fate but the good news is that, whilst powerful hot water heaters commonly fall victim to the fish oil smell and burning connections problem, lighting circuits and light fixtures rarely do.

The photograph above shows a wire that has burnt out above a light fixture. This was a result of the heat generated by the bulb / lamp that was installed in the fixture. 

The less powerful the electrical circuit the less frequently we seem to see this problem. Common sources appear to be:

• Hot water tank electrics
• Electric Heater Circuits
• Electric Cookers
• Electric Showers
• Wall Outlet and plug sockets

9) Summary

If you can smell pungent plastic, fish odor or other strange smells in your own home then it is likely that there is an electrical issue. 
Where there is a FISHY SMELL IN CUPBOARD there is likely a switch or other electrical accessory installed in there causing the issue. When dealing with the problem, ask your electrician to make sure that the switch is of the right type for the load and that it is accessible for any future problems.