I am an engineer, but not an electrical one

I recently got a bidet toilet seat that has a built in water heater. This causes all the lights in the adjoining rooms to flicker rapidly. It's very annoying because it happens a few times per hour as the bidet reheats the water in the tank and also, I presume, the seat. I tried using a hair dryer and the lights do dim but it's not unpleasant, and it doesn't seem abnormal even when drawing almost double the wattage of the bidet. Same with a space heater. And I even tried a toaster. So I think the bidet is using some kind of pulsing or otherwise electrically "dirty" method to create heat. Can anyone suggest some kind of filter or conditioner that I can build to use in-line with the bidet to clean this up? I assume a pre-made device does not exist on the market already but would love suggestions if you know of something. If it matters, the outlet for the bidet is GFCI'd with an external GFCI receptacle on top of a standard outlet.

 

First things first.
Check the power requirements as printed on the label of all the devices involved.
Check the rating of the service panel and the fuse or circuit breaker.
Have an estimate of the length of the electrical cabling to the heater and the size of the cable.

After you've done all of that to your satisfaction, called a certified electrician to check your wiring and installation.
An overloaded circuit is a dangerous fire hazard.

 

It could also be bad ground, have it checked immediately!

 

If the flickering is caused by the bidet heater being rapidly switched on and off, then it would be difficult to build a filter to suppress that.
You either need larger wire from the bidet to the breaker box, or connect the bidet to a different circuit that isn't shared with the lights that flicker.

 

I appreciate the concern but I already ruled out the wiring being an issue here. The bidet draws 7 amps on a 20 amp circuit. I tested the same outlet with a hair dryer that pulls 15 amps and the lights dim slightly - about the same as every other home i've ever lived in, it's nothing out of the ordinary.

Also, I have some old "smart bulbs" that don't flicker while all my "dumb bulbs" do - so that is an indication to me that it is possible to overcome this noise using a more robust power supply. Unfortunately, I can't change the ceiling fixtures to use these bulbs.

 

As an update, I just tried measuring the circuit with a digital multimeter. The voltage drop is significant but does not strike me as dangerous.. but I'm reaching at the edges of my knowledge of electricity here. We see a 4v drop with the heater running. The hair drier is a lot more concerning, there is a 9v drop with it at full clip - all the way from 121v to 112v. Also, I miscalculated the draw on the hair dryer - it's not 1600w, it's 1900w!

As a reminder, the issue is not that the lights dim, it's that they rapidly flicker. I can live with the lights dimming intermittently.

 

What is the heater wattage
What is the wire run from the breaker
What the wire gauge
Is this 120V?

 

@Wolframore, did you see my second post? We posted at about the same time so it's possible that you only saw my first reply.

The heater is 850w. The circuit is 120v. The wire gauge on the bidet itself is 18 gauge, 3 prong, 6 feet.

I don't know what the wire in the walls is like, but I can give you a rough guess that the run to my panel is about 35-40 feet, just drawing lines in my head from the outlet down to the floor and then over to the wall, down to the panel, etc.

 

I don't know what the wire in the walls is like, but I can give you a rough guess that the run to my panel is about 35-40 feet, just drawing lines in my head from the outlet down to the floor and then over to the wall, down to the panel, etc.

Just because it has a 20Amp breaker doesn't mean much if the wire run isn't the right size/gauge for 20Amp. I've seen, in older houses, some people put a higher amp breaker on a low amp wire thinking it will solve their problems. What gauge is the wire coming from the 20Amp breaker?

 

assuming the bidet is pulsing, the average current might be 7A but the peak current could be much higher, hence the flickering of the lights.

Bob

 

As a reminder, the issue is not that the lights dim, it's that they rapidly flicker. I can live with the lights dimming intermittently.

Wrong. The issue is not the flicker. The issue is the dim lights.

4V x 7A = 28W
9V x 15A = 135W

You are generating 28W and 135W as heat along the lines.
Check the gauge of the wire.
Look for hot spots (preferably with a thermal imaging camera) at all connections, junctions, outlets, plugs, etc.

 

I would contact the manufacturer and ask their advise on a line reactor. They will certainly have had to field the complaint.

 

I can't change the ceiling fixtures to use these bulbs.

Why do you need to change the fixture?

 

@MrChips I genuinely appreciate your concern but this flicker would be present even if the circuit was perfect, and I'd be on this forum asking the same question. I know this because I just tested it. Running the hair drier on lowest setting and pressing the "cool" button causes noticable dimming and shows a 1.4v voltage drop on my multimeter. With either the LED or an incandescent running, if I press the button rapidly it's annoying to look at. The bottom line is that the heater is pulsing at a frequency that is low enough to be noticable to the human eye.

I did email the bidet manufacturer but I'm not expecting much.

 

Why do you need to change the fixture?

I don't need to change the fixture, but using these specific tcp bulbs are the only solution I've found so far and they don't fit in the ceiling fixtures.

@GetDeviceInfo
I googled line reactor, doesn't look like the kind of thing you pick up at best buy, but maybe I can build one or repurpose one into the bidet?

 

As an update, I just tried measuring the circuit with a digital multimeter. The voltage drop is significant but does not strike me as dangerous.. but I'm reaching at the edges of my knowledge of electricity here. We see a 4v drop with the heater running. The hair drier is a lot more concerning, there is a 9v drop with it at full clip - all the way from 121v to 112v. Also, I miscalculated the draw on the hair dryer - it's not 1600w, it's 1900w!

As a reminder, the issue is not that the lights dim, it's that they rapidly flicker. I can live with the lights dimming intermittently.

anything over 0.1V is a problem. if you don't think 4V or 9V drop is an issue you need to see what the power loss is equivalent to.
4V*7A = 28W. there are several soldering irons that consume less (12W, 15W, 18W, 25W). if you think having one or more soldering irons inside each connection box in your wall is not a problem, you should have no problem calling your home insurance and see how they like the idea.

you need to check wire gauge and connections on that line, looks for oxidation, retighten and preferably replace the connectors (marrets).

 

I don't need to change the fixture, but using these specific tcp bulbs are the only solution I've found so far and they don't fit in the ceiling fixtures.

@GetDeviceInfo
I googled line reactor, doesn't look like the kind of thing you pick up at best buy, but maybe I can build one or repurpose one into the bidet?

One should consider the allowable voltage drop in a branch circuit, which by code is 3%, at 80% of circuit current rating, due to conductor impedance. In such a case, the resulting heat dissipation is over the length of the conductor, and of little cause for concern. Excessive drop can also occur at a specific point, such as a connection, which can generate excessive heat at that point. We may see this as a burnt receptacle for instance. One should access that they are not overlooking such a scenario, of which excessive voltage drop is often a clue. If the manufacturer denies their product being a problem, that should be another tip that problems lie elsewhere. The only responsible (and legal) recommendation I can make is to call in a pro.

 

According to the voltage drop calculator I just found, 15 amps will drop a tenth of a volt on 10 gauge wire at 3 feet. At 40 feet, 14 gauge, we're at 3.2 volts. Copper conductors. Aluminum at 12gauge is a tenth of a volt more.

 

This would still be a noticable issue even if the circuit was brand new, installed correctly, and had 8 gauge wire. Does anyone have a suggestion that addresses the pulsing?

 

This would still be a noticable issue even if the circuit was brand new, installed correctly, and had 8 gauge wire. Does anyone have a suggestion that addresses the pulsing?

Call the manufacturer. If its equipment related, they may have a solution, and might even send that solution to you free of charge.