Your Resident Electrician for all your electrical questions!

[Sleepydoc]

Need some help with a relay.

I want to run a USB air pump to run a skimmer but I want to have it shut off if the water level drops too low. Is there a 5 volt relay that can work off a float switch?

Usually the problem with skimmers is if the water level is too high. The issue is the current, not the voltage. Float switches can only handle very low current loads. The coils in relays can also cause voltage spikes when the switch on and off. You’d be best off having an interface between the float switch and the relay.

 

[Ray Laneville]

@Paul B

 

[salty150]

So, my understanding is that each 15A circuit can handle safely about 1440W - correct?

So, if you have more than 1400W - say 2400W - can you just split the load by plugging half the equipment into one outlet - and then the other half into a different outlet on a different circuit/breaker?

I assume so... but I have learned the hard way never to assume...

 

[Turbo's Aquatics]

So, if you have more than 1400W - say 2400W - can you just split the load by plugging half the equipment into one outlet - and then the other half into a different outlet on a different circuit/breaker?

yes

 

[waitwut]

Just want to sanity check my thinking - I am concerned about both fire protection/safety and also minimising the risk of a stray drip or a faulty heater tripping a main RCD while I'm out and taking out my entire tank along with half my apartment. I already have RCD/GFCI devices installed in my junction box (I'm in Europe so they're mandatory) - there's two of them with the circuits split between them.

I'd like to install another RCD/GFCI device just on the circuit for the room with my aquarium - that way if it does trip, my internet stays on and I can still get a notification out from my GHL Profilux to warn me. Also reduces the risk of an issue in another part of the apartment taking out the aquarium as well.

I'm planning to replace the breaker for this circuit with a combination RCD/circuit breaker installed in parallel with the existing RCD devices (not after them). It's rated the same as the existing breaker (16A) and the existing RCD devices (30mA). Am I correct in thinking these are ok to be connected directly to the power supply coming into the apartment? i.e not after another RCD/main circuit breaker like the regular circuit breakers for the other circuits - the RCD devices are also 40A breakers.

Also, is there any value in adding in RCD/circuit breakers on the individual power strips (either plug-in devices or hard wired ones like this)? It would be amazing if I could isolate a power cut due to ground leakage down to a single power strip like you can with GFCI outlets, would a 10mA RCD like that reliably trip before a 30mA one in series or are they likely to trip together? Is 10mA too sensitive? Now that I type it out I guess it's probably down to the reaction time more than the sensitivity and these cheap things are not likely to win that race . . .

I do like the idea of having individual circuit breakers/overload protection on each power strip to potentially reduce the risk of a fire but I don't think 16A is going to be useful as the whole circuit has a 16A breaker on it already, maybe 10A would offer some protection?

Down the line I may run in new cabling for a dedicated circuit and wire up a junction box dedicated to the aquarium but that's too much right now - and it's not really drawing that much power . . . yet . . .

 

[Confused]

Just want to sanity check my thinking - I am concerned about both fire protection/safety and also minimising the risk of a stray drip or a faulty heater tripping a main RCD while I'm out and taking out my entire tank along with half my apartment. I already have RCD/GFCI devices installed in my junction box (I'm in Europe so they're mandatory) - there's two of them with the circuits split between them.

I'd like to install another RCD/GFCI device just on the circuit for the room with my aquarium - that way if it does trip, my internet stays on and I can still get a notification out from my GHL Profilux to warn me. Also reduces the risk of an issue in another part of the apartment taking out the aquarium as well.

I'm planning to replace the breaker for this circuit with a combination RCD/circuit breaker installed in parallel with the existing RCD devices (not after them). It's rated the same as the existing breaker (16A) and the existing RCD devices (30mA). Am I correct in thinking these are ok to be connected directly to the power supply coming into the apartment? i.e not after another RCD/main circuit breaker like the regular circuit breakers for the other circuits - the RCD devices are also 40A breakers.

Also, is there any value in adding in RCD/circuit breakers on the individual power strips (either plug-in devices or hard wired ones like this)? It would be amazing if I could isolate a power cut due to ground leakage down to a single power strip like you can with GFCI outlets, would a 10mA RCD like that reliably trip before a 30mA one in series or are they likely to trip together? Is 10mA too sensitive? Now that I type it out I guess it's probably down to the reaction time more than the sensitivity and these cheap things are not likely to win that race . . .

I do like the idea of having individual circuit breakers/overload protection on each power strip to potentially reduce the risk of a fire but I don't think 16A is going to be useful as the whole circuit has a 16A breaker on it already, maybe 10A would offer some protection?

Down the line I may run in new cabling for a dedicated circuit and wire up a junction box dedicated to the aquarium but that's too much right now - and it's not really drawing that much power . . . yet . . .

I'm not from Europe. You can always add a down stream GFCI, (never heard of RCD resident current devices, think thats an outlet.) but If I'm understanding this, you are getting false trips? anyways no breakers should be tripping, unless you did it on purpose. you're 110% best option is to call a local sparky and just tell him what happening and what you'd like and get a few quotes.
I wouldn't go above 20 amps As for my tank I ran a single 30 amp circuit with #10 on a Highspeed 20amp outlet Nema 5-20 non GFci/AFci mounted high, from there I have a 2500watt UPS (Uninterruptible Power Supply) with all my important stuff on the UPS and less important stuff on a basic but not cheap surge protector. so on a power failure my tanks return, waves, and heat all stay on but lights and silly things shutoff. my tanks in the basement my panel is 20 feet away with open ceilings as a licensed electrician took me 25 minutes and 40 bucks in parts that I mainly "stole" from work haha.
My tank is 90 gallons and I use at max with lights and heaters and everything going at once which is rare but I max out at 1000 watts if I round up, 1000w / 120v = 8.3amp and an standard 20 amp breaker can hold 80% of it value so a 20 amp breaker is good for 16 amps and below forever. but you hit 17amps you might get 2 hours you might get 2 weeks before it trips due to the time inverse delay of breakers, you can buy an AMP probe and take some amp readings to see how much your tank is pulling. if your having electrical problems always call a local electrician.

From my time in the field I spend a lot of time replacing GFCi/AFCi breakers and outlets that failure, or that are just casing nuisance tripping to fridges or server racks. If your outlet is near a sink, shower, piped in water source (forever water from ground), you're stuck using a GFCi. Me personally would not call a fish tank a water source unless you have hard copper pipe to it.

sensitivity is set at the factory. some are more sensitive then others, you don't want to look at tuneable breakers you'll need to hire a man to set it. its a real nightmare and like 1000s of bucks a breaker. tend to find them in factorys or hospitals as long as you've been wired up to the NFPA70 the bare spec fires and stuff very very very unlikely to happen, you would have to purposely start a fire with it.

Hopefully that answered something for ya.

 

[Paul B]

I wouldn't go above 20 amps As for my tank I ran a single 30 amp circuit with #10 on a Highspeed 20amp outlet Nema 5-20 non GFci/AFci mounted high,

I don't exactly understand this (and I am a master A Rated Electrician)
You can't legally install a 20 amp outlet on a 30 amp circuit breaker.

What is a "High Speed 20 amp outlet?"
I retired almost 20 years ago so maybe it's a new thing.

 

[Confused]

I don't exactly understand this (and I am a master A Rated Electrician)
You can't legally install a 20 amp outlet on a 30 amp circuit breaker.

What is a "High Speed 20 amp outlet?"
I retired almost 20 years ago so maybe it's a new thing.

I apologize miss type its a Nema 6-30, its a 30 amp double straight. the APC 2500 requires this.