To GFCI or not to GFCI

chadan · Sep 7, 2021

I have a 150 gallon reef tank (an aquarium for the uninitiated). I had 2-20amp circuits installed to run everything. Not close to max amps. Given that GFCI’s can trip in a false over-current situation, they are somewhat unreliable and my tank can die within hours of power failure is a GFCI still recommended? All power cords have drip loops and are away from possible leaks. Advice???

pc1966 · Sep 7, 2021

You might need to wait for one of the USA members such as @Megawatt to answer this, as most of us are UK-based so the regulations are somewhat different.

In the UK if you don't want to use an RCD (our name for GFCI) for a circuit and it meets certain other requirements (no unarmoured buried cables < 50mm that could be drilled/nailed, etc) then you would hard-wire it in to a fused connection unit instead of using a plug & socket.

However, an aquarium is an interesting case as it is almost like a swimming pool, but not for humans! That normally has to have RCD protection in the area and only safe low-voltage stuff inside it. However, my ancient experience of aquariums is they use mains supply for heaters & pumps and often you are arm-deep cleaning stuff. Tricky...

If you had to use an RCD and were afraid of power loss then options are to alarm the system, or to look at auto-recloser RCDs, but they cost a lot.

pc1966 · Sep 7, 2021

Here is an example, don't know if they do a USA voltage version:

A9C70132 | Auto Recloser Circuit Trip for use with Circuit Breaker | RS

uk.rs-online.com

chadan · Sep 7, 2021

pc1966 said:
You might need to wait for one of the USA members such as @Megawatt to answer this, as most of us are UK-based so the regulations are somewhat different.

In the UK if you don't want to use an RCD (our name for GFCI) for a circuit and it meets certain other requirements (no unarmoured buried cables < 50mm that could be drilled/nailed, etc) then you would hard-wire it in to a fused connection unit instead of using a plug & socket.

However, an aquarium is an interesting case as it is almost like a swimming pool, but not for humans! That normally has to have RCD protection in the area and only safe low-voltage stuff inside it. However, my ancient experience of aquariums is they use mains supply for heaters & pumps and often you are arm-deep cleaning stuff. Tricky...

If you had to use an RCD and were afraid of power loss then options are to alarm the system, or to look at auto-recloser RCDs, but they cost a lot.

!!!! GOOD! So added detail…system is alarmed against power failure. Also alarmered against device failure but stray voltage can be a problem in this hobby but I am concerned 1) with fish electrocuted then me (because it would happen in that order. 2) false tripping of GFCI due to “common” power spikes/surges caused by heaters and power heads starting up. I have many devices that will cause small power surges when starting up that come on and off during the day. My smart power strip has power monitoring and can be programmed to cut power in certain situations.

Megawatt · Sep 8, 2021

chadan said:
!!!! GOOD! So added detail…system is alarmed against power failure. Also alarmered against device failure but stray voltage can be a problem in this hobby but I am concerned 1) with fish electrocuted then me (because it would happen in that order. 2) false tripping of GFCI due to “common” power spikes/surges caused by heaters and power heads starting up. I have many devices that will cause small power surges when starting up that come on and off during the day. My smart power strip has power monitoring and can be programmed to cut power in certain situations.

My friend the 2020 Edition of the NEC doesn’t mention aquariums but if it was my aquarium I would not plug it into a GFCI. If you think about it there is no difference of potential between the water and really nothing so I really cant see how a GFCI Receptacle would help you anyway. Good luck with your fish.