Electrical fault

[Jim Lay]

My Interpet PF1 filter blew all my main house socket's circuit breaker. The problem was a cable fault where the mains goes into the pump unit - (at the top of the pump). Due to the removal and re-installation of the pump/filter for cleaning, over the years, the tiny wires going into the pump had hardened and cracked - this caused a short which burnt the insulation and blew the circuit breaker. This happened at 11.30 pm. If it hadn't been for my bedside clock going off, I would have lost my lovely fish. This also an electrocution possibility. Check Pump/filter wiring!!!

 

[AbbeysDad]

Another good example of how all aquarium powered devices (lights, filters, air/water pumps) should be plugged into a Ground Fault Interupter Circuit (GFIC). You can purchase units that plug into your regular outlet(s), then your devices plug into it. Why? At the slightest hint of a electrical short, the internal breaker will trip, ensuring that no person or animal is electrocuted...a push of a button resets the unit.

 

[Jim Lay]

Hi AbbeysDad
I'll have a look at that gizmo.
Thanks for the info

 

[Essjay]

Searching does not produce any results for GFIC's on sale in the UK. Since our wiring works a different way, I'm not sure what the equivalent is? An RCD?

 

[Jim Lay]

Hi Essjay
Found many Ground Fault Interupter Circuit breakers for uk on a Google search. But would they cut the circuit before the main breaker in the house fuse box cuts all the power - as was the case with my Filter ???

 

[Essjay]

OK, just asked my electrician son. This is being dictated by him:

American wiring works differently - it uses a 2 pin system, we have a 3 pin system. All UK aquarium products are double insulated, they have only live and neutral, they don't have an earth. As they don't have an earth, using a plug in 'circuit breaker' (RCD) is pointless as these rely on an imbalance of current between live, neutral and earth to detect a fault or short.
The house's consumer unit (the "fuse box" or "circuit breaker box") will detect a short between live and neutral and trip. You don't need a plug in device.
Basically - in the UK, the consumer unit is enough protection. Yours did exactly what it was supposed to do. But check the cables on aquarium equipment regularly.

That's the simplified version - he also talks about MCBs and RCDs and what the difference is, and how they have to trip in how many milliseconds which is way above my head
I think he's saying that because aquarium equipment in the UK doesn't have an earth, there can't be a short between neutral and earth or live and earth, there can only be a short between live and neutral and a plug in RCD can't detect that type of short.

 

[Colin_T]

Australia has a 3 pin power socket and some electoral appliances have 2 pins and others have 3 pins. Most aquarium electrical appliances have a 2 pin plug.

I used power packs that had 6 sockets with a built in circuit breaker on my tanks. These power packs had a 3 pin plug and got plugged into a wall power point/ socket. They tripped a couple of times but it was rare.

For the OP, how old was your Interpet PF1 filter?

 

[Jim Lay]

Hi Colin_T
The PF1 filter was about 6 years old. The filter is powered with a positive and negative wire only - 2 wires. They shorted out 'together' and blew the mains RCD. Would a seperate 'plug' RCD stop the mains RCD cutting out all the sockets - that's what happened with me. This caused the tank's heater to be disconnected - that's the problem. I'm just lucky that my bedside light went out and I could then find the culprit and disconnect the filter - heater back on. 'Well done', I concluded - new filter on order. I suspect the wires had age-hardened and cracked the insulation - BANG.

 

[Essjay]

According to my electrician son, plug in RCDs only detect neutral-earth and live-earth shorts. Since aquarium equipment doesn't have an earth wire, they can only have neutral-live shorts and plug in RCD's don't detect those.
Your consumer unit has MCBs and RCDs and MCB's can detect live-neutral shorts (or something like that, it got a bit complicated for me), which is what yours did.

Edit:
He showed me the diagrams of consumer units, and the mains electricity passed through an MCB to the individual circuit RCDs. Some consumer units have 2 MCBs and good practice is that the RCDs for downstairs ring main and upstairs lights run from one MCB, and upstairs ring mains and downstairs lights run off the other. This is so that both upstairs and downstairs have some form of lighting available if one of the MCBs trips - either in the ceiling or a plug in light.

 

[StevenF]

OK, just asked my electrician son. This is being dictated by him:

American wiring works differently - it uses a 2 pin system, we have a 3 pin system. All UK aquarium products are double insulated, they have only live and neutral, they don't have an earth. As they don't have an earth, using a plug in 'circuit breaker' (RCD) is pointless as these rely on an imbalance of current between live, neutral and earth to detect a fault or short.
The house's consumer unit (the "fuse box" or "circuit breaker box") will detect a short between live and neutral and trip. You don't need a plug in device.
Basically - in the UK, the consumer unit is enough protection. Yours did exactly what it was supposed to do. But check the cables on aquarium equipment regularly.

That's the simplified version - he also talks about MCBs and RCDs and what the difference is, and how they have to trip in how many milliseconds which is way above my head
I think he's saying that because aquarium equipment in the UK doesn't have an earth, there can't be a short between neutral and earth or live and earth, there can only be a short between live and neutral and a plug in RCD can't detect that type of short.

That is not quite correct:
The US has 3 pin system (hot, neutral, ground) just like all countries in the world. If a product has a metal case that can conduct electricity the case must be connected to ground. In the case of an aquarium pump with a non conductive plastic case a ground connection is not required. The the plastic case makes it double insulated.

A typical circuit breaker will only detect a short between the hot and neutral wires. It may not detect a short between hot and ground pins of the outlet.

A ground fault interrupter detects a short between ground and the hot wire or ground and the neutral wire. Many GFCI also protect against a short between hot and neutral. But not all do. Typically ground faults have a resistance of 1 million ohms to 10,000 ohms and as a result ground faults often don't trip circuit breakers.

Bit it is important to note that a GFCI may not provide any protection for an aquarium. Many aquariums today are made from glass and plastic or just plastic. Neither conducts electricity. So a fault in the pump can electrify the tank water and yet not trigger a GFI or home circuit breaker. and it would not kill or affect the fish. This is because the water is not grounded. People have reported being shocked when they performed their normal weekly water change. Although at this point I have not heard of anyone dying.

for optimal protections replace the wall outlet with +GFCI outlet and then run a stainless steel wire from the ground pin on the outlet to the tank water . That way if the aquarium water is electrified power will flow from the pump or heater or lamp through the water to the ground wire. And when that happens the GFCI will trip. If the power and neutral short the the home circuit breaker will trip and maybe the GFI will trip.

 

[Essjay]

Those GFCI's can be used in the US but not in the UK. The way our electrical system is wired is different and they wouldn't work. That's why google can't find any for sale in the UK, only those on American sites.

 

[eatyourpeas]

Another good example of how all aquarium powered devices (lights, filters, air/water pumps) should be plugged into a Ground Fault Interupter Circuit (GFIC). You can purchase units that plug into your regular outlet(s), then your devices plug into it. Why? At the slightest hint of a electrical short, the internal breaker will trip, ensuring that no person or animal is electrocuted...a push of a button resets the unit.

I have been slowly switching my whole house to GFI just to be safe. Then again, the wiring in this house was horrible to begin with. We found cracked wires inside the walls!

 

[Essjay]

Can I just point out that different countries have different wiring regulations. We need to work with whatever regulations are in place in any particular country. The OP gives his location as the Orkneys which come under UK wiring regulations, so giving advice to him based on US wiring regulations, or the regulations of any other country, are useless for him.

By all means give advice based on wiring regulations to someone living in the same country, but not to members living in countries with different wiring regulations.


Thank you.

 

[Jim Lay]

Thanks everybody for taking on this subject. I know that the problem I experienced was due to the two little piddly wires, that power my PF1 filter unit, shorting out under water - that's where they enter the filter body.
This was caused - I am certain - due to age hardening of the cable's insulation enabling the 240 volts to short out together. Also, the filter is cleaned pretty regularly, which means that the filter is removed from the tank and, due to my mishandling (possibly) the plug hangs down from the filter. The power cables are barely 1mm OD and the continuous maltreatment I exposed them to caused the hardening and and cracking of the insulation. An education in how NOT to handle these pathetically useless cables. I will be working out how to provide support for the cables on the new PF1 - there must be a solution.
I would warn everyone who has a power filter/pump to check out their wiring. Plus. if you don't have a Circuit Breaker fused power system in your house - get one installed NOW on your filter.
Thanks again everyone.
Good fishing
Best regards Jim Lay

 

[mcordelia]

@Essjay hear hear on the variety of electrical systems. Having lived both in Europe and the US, I have to say the 240v system is a lot more intelligently designed. In most european countries' plugs/wiring, as @DAnCSF correctly described, the ground is in the casing itself. Thus, there is not always a third prong, and a GFCI is useless because there is nothing for it to detect.

However, the risk of electrification of the water is still a possibility, since the expectation is that the casing will conduct any errant electrical currents, and if the current instead escapes into the water then it cannot trip the circuit in the main breaker. In general, the 240 casing-grounded system is less likely to trip a circuit in general, since (among other factors) the current delivered is smaller than that delivered by the american wiring system, since you can get more power with less current if your voltage drop is twice as much (240v vs. 115v). V=IR and all that other good stuff about ohms law

If, in the exceedingly rare circumstance that one wishes to avoid being "zapped" by their tank water, a metal wire run to a large enough metal object that can act as "ground" - preferably a metal water pipe or sacrificing a plug and running it to the casing (most european grounded outlets have a metallic thing that is not one of the two wires - italian ones have a central "hole", scandinavian ones have two metal strips on both sides of the plug, and I believe the UK version also has a hole, though in a triangular configuration.) I am sure your son would have a heart attack over someone suggesting running an exposed wire to the ground prong in the outlet, sooo, for the purposes of most folks this is probably not necessary.

As I was double checking myself on google, I also learned that most UK grounded plugs have a fuse built in to the plug in many situations, meaning that this would be a moot point if the aquarium plug is of the grounded type. However, observing my heater and filter and light plugs on my tank currently, none of them are grounded, so if this is also the case with most UK equipment, you don't get the benefit of the fuse in the grounded plug itself.

By the way, I highly recommend reading up on the history of electricity and how most of the world ended up with a 240v standard compared to the 115v standard of the US. interesting reading!!

This probably did nothing to clarify for anyone, but for some reason I felt compelled to join the conversation