House Power Mystery

Doublej · « **on:** 31 Dec 2020, 10:09 pm »

I just purchased an 1800 watt Breville toaster oven. It's plugged into the kitchen circuit but lights on other circuits flicker when the toaster oven is in use. The house has a 100 amp circuit.

Does anyone know why and how (much it might cost to have an electrician come in) to fix it?

This issue has triggered an unrelated question, Should circuit breakers be replaced due to age and if so how often? The panel and circuit breakers are at least 20 years old.

Big Red Machine · « **Reply #1 on:** 31 Dec 2020, 10:28 pm »

Well, appliance circuits should be dedicated and no lights should be tied in. Do you know which circuit is which and are they on GFCI's along the countertops and islands?

Have you tried using an extension cord to troubleshoot using it on a different outlet or circuit?

CB's are only $5 to $10 each for your needs and you could replace them yourself if you are careful. Hopefully your circuits are wired correctly.

You could also get a simple wand and plug in module to trace your outlets back to your breakers and make your own layout. Probably $20 to but one IIRC.

I'm sure an electrician will charge you at least $200 to investigate unless he's a good ole boy and you might get a break. I'd do it for free.

Doublej · « **Reply #2 on:** 1 Jan 2021, 01:33 am »

I have each electrical outlet and hard wired light mapped back to the circuit they are on. Yes the kitchen countertop outlets are GFCI outlets. The flickering is on lights that are on the same circuit and on lights that are not on the same circuit as the toaster oven.

I have checked all outlets in the house with a receptacle tester and the tester is indicating that each outlet is wired correctly.

I have not tried the toaster oven on a different circuit using an extension cord. That will be tomorrow's activity. Stay tuned for a report.

Doublej · « **Reply #3 on:** 4 Jan 2021, 01:39 am »

Tried it on a different circuit and the problem still exists.

FullRangeMan · « **Reply #4 on:** 4 Jan 2021, 06:20 am »

Lights flicker on other circuit why the voltage had a drop below the minimum expected by the lamps.

How many brakers you have in the panel?
How many amperage they are?
What gauge are the wiring ?
What are the wall voltage level though the day?

Speedskater · « **Reply #5 on:** 4 Jan 2021, 01:59 pm »

Get a little 'Kill-a-Watt' meter. Measure the voltage on several circuits in the house with and without the oven operating.
It suggests either a failing connection or a 'lost Neutral' problem.

Peter J · « **Reply #6 on:** 4 Jan 2021, 03:13 pm »

Assuming "100 amp circuit" means 100 amp service, I'm assuming either an old house and/or retrofit of the breaker box that may have been a fuse box. The demand for electricity within houses has increased dramatically over the last couple of decades. Any new home will have a minimum of 200 amp service and 2 or even 3 200 amp panels is not unheard of. Add to that copper home wiring slightly builds resistance over time, so becomes less efficient at its job.

At 1800 watts you're drawing about 15 amps, which is significant. And it's a heating element which will be full demand right at startup. We could go into the need for dedicated 20 amp GFI circuits in your kitchen, but sounds like what's happening is the inrush current of the oven is taxing the system and reducing voltage to the lights. The Kill-A-Watt meter can tell you what's happening, but won't do anything to solve.

I would make sure all connections in panel are good and tight. Also check associated receptacles and in-box wire nuts. If the wiring integrity is as good as it can be, it may not be easily fixable. Also might be a good idea to check function of associated breaker. The phenomenon happens in almost any electrical system, but there's enough over capacity to compensate and not rob Peter to pay Paul in a noticeable way.

Depending on length of time oven is running, it may be heating up the in-wall wiring, which isn't good, but not necessarily dangerous. It'd be wise to figure out what's happening to best assess risk. The oven isn't doing you any favors, but perhaps pointing up areas of concern.

If you don't feel confident in your own abilities to troubleshoot, I'd really recommend you consult a savvy electrician.

Elizabeth · « **Reply #7 on:** 4 Jan 2021, 05:43 pm »

Back at the wires coming into the house yes right where they enter, check them for damage, corrosion. Or on the main panel, check the wires. there may be a damaged wire.
Something may be causing a restriction in the current prior to the breaker box..

Don_S · « **Reply #8 on:** 4 Jan 2021, 05:59 pm »

Check all the grounding connections at the grounding buss. My electric in-wall oven kept blowing control boards. The ground was loose. The clock and display worked until more power was needed for cooking then the weak ground killed everything.

That may not be your problem but it is still a good item to check on an older service.

thunderbrick · « **Reply #9 on:** 4 Jan 2021, 06:17 pm »

Quote from: Don_S on 4 Jan 2021, 05:59 pm

Check all the grounding connections at the grounding buss. My electric in-wall oven kept blowing control boards. The ground was loose. The clock and display worked until more power was needed for cooking then the weak ground killed everything.

That may not be your problem but it is still a good item to check on an older service.

Same situation on my home and my wife's lakeside cabin. Cleaning/tightening the ground solved it in both cases. The local utility guy said his boss always tells them to do that first.

rollo · « **Reply #10 on:** 4 Jan 2021, 09:03 pm »

Requires a dedicated 20 Amp line.

charles

FullRangeMan · « **Reply #11 on:** 4 Jan 2021, 10:55 pm »

Quote from: Elizabeth on 4 Jan 2021, 05:43 pm

Back at the wires coming into the house yes right where they enter, check them for damage, corrosion. Or on the main panel, check the wires. there may be a damaged wire.
Something may be causing a restriction in the current prior to the breaker box..

The consumption meter is very important to the energy quality, in addition to the corrosion I would like to add that the wires that arrive in the consumption meter will slowly loosen up over the years of use due to the vibration of the 60Hz cycling, I found this on my consumption meter and had to retighten the wires which stm decreased the consumption a bit.

Doublej · « **Reply #12 on:** 5 Jan 2021, 07:21 pm »

Here is what the ground from the electrical meter looks like. Looks like a big contributor to the problem. Does the power company have the responsibility to address this or is it me the owner?

rollo · « **Reply #13 on:** 5 Jan 2021, 08:52 pm »

You could clean it and reconnect. Then pour water around ground rod better when wet.
charles

Speedskater · « **Reply #14 on:** 5 Jan 2021, 09:47 pm »

The main task of the Safety Ground is to trip the circuit breaker (or fuse) in the event of a 'ground fault' (short circuit).
The connection to Planet Earth has nothing to do with the problem. Or for that mater day-to-day operation of the AC power system (or it's quality).

Doublej · « **Reply #15 on:** 5 Jan 2021, 11:48 pm »

Kill A Watt meter has been ordered.

Doublej · « **Reply #16 on:** 7 Jan 2021, 02:07 am »

Some quick test results using a small fan space heater. Should the voltage be dropping so much under load?

Bathroom Outlet:
Off - 122.8V, 0A
Fan only - 122.2V, .2A,
Low Heat - 112.4V, 7.8A
High Heat - 108.5V, 11.2A

Kitchen Outlet:
Off - 123.4V, 0A
Fan Only - 123.3V, .2A
Low Heat - 118V 8.2A
High Heat - 116.2V 11.9A

Bedroom:
Off - 120.8V, 0A
Fan - 120.7V, .2A
Low Heat - 114.6V, 8.0A
High Heat - 112.7V, 11.7A

FullRangeMan · « **Reply #17 on:** 7 Jan 2021, 02:30 am »

Quote from: Doublej on 7 Jan 2021, 02:07 am

Some quick test results using a small fan space heater. Should the voltage be dropping so much under load?

Bathroom Outlet:
Off - 122.8V, 0A
Fan only - 122.2V, .2A,
Low Heat - 112.4V, 7.8A
High Heat - 108.5V, 11.2A

Kitchen Outlet:
Off - 123.4V, 0A
Fan Only - 123.3V, .2A
Low Heat - 118V 8.2A
High Heat - 116.2V 11.9A

Bedroom:
Off - 120.8V, 0A
Fan - 120.7V, .2A
Low Heat - 114.6V, 8.0A
High Heat - 112.7V, 11.7A

What is this hi amperage value of 11A ?
How do you came to it?

Doublej · « **Reply #18 on:** 7 Jan 2021, 02:53 am »

With the space heater on high heat the Kill A Watt meter shows that 11 amps is being drawn by the space heater.

With the Kill A Watt meter plugged into the bathroom outlet, I turned the toaster oven on and the voltage on the bathroom outlet went up to 126V. Is this normal?

FullRangeMan · « **Reply #19 on:** 7 Jan 2021, 03:06 am »

Quote from: Doublej on 7 Jan 2021, 02:53 am

With the space heater on high heat the Kill A Watt meter shows that 11 amps is being drawn by the space heater.

With the Kill A Watt meter plugged into the bathroom outlet, I turned the toaster oven on and the voltage on the bathroom outlet went up to 126V. Is this normal?

With the space heater on high heat the Kill A Watt meter shows that 11 amps is being drawn by the space heater.
OK. so this is a really very big heater wow, in view of this the voltage drop on other room may be acceptable.
With the Kill A Watt meter plugged into the bathroom outlet, I turned the toaster oven on and the voltage on the bathroom outlet went up to 126V. Is this normal?
This unusual not good, I cant explain this imbalance without in loco inspection.

Worth mention when I worked in a steel plant we found that the electrical grounding with resistance above 3 ohms was not fast enough to save expensive computer equipment in the event of lightning rain. On average the grounding had a resistance of 1 ohms for only 6 months using a 3 meter copper bar.