Heat Pump Startup Makes The Lights Flicker,,, Is That OK??

[MossRoad]

My 400 amp meter base, supplied by the electric coop, feeds 2 panels. Each has a main breaker, 225 amp for the house and 175 amp for the stables. If I remember correct you are allowed up to 6 disconnects within a certain distance of the meter base.

I think you probably have a double lug meter base if you're feeding two panels directly from the meter to two separate buildings.

I've read a bit on the 6 disconnect rules. They are confusing to read without a diagram to follow. From what I have read, if you have multiple disconnects, they have to be grouped either in one box, a group of separate boxes, on a switchboard, or in a switchboard. If you have more than one disconnect at a service, they must be grouped. This is for safety, as in, if the fire department shows up at your house, they can find all of the disconnects in one place.

When we had our meter moved from one side of the house to the next side, they told us there was a maximum distance that could be between the meter and the service disconnect. If we wanted the main breaker in our panel to be the service disconnect, the panel would have to be located within X feet. I think it was pretty short, like 10-12' at most. If it would have been any further, we would have had to install a service disconnect right below the meter, and that would then be considered the first panel in the system, so our "main" electrical panel in the house is not the "main". It's a sub panel from the service disconnect under the meter.

Now I'm curious. On your setup, your service feeds your meter. Then you said you have wires feeding a panel for the house, and a panel for the stables. Is there no disconnect switch(s) at the meter for either of those feeds? How far are those house and stable panels from the meter?

 

[WM75Guy]

Now I'm curious. On your setup, your service feeds your meter. Then you said you have wires feeding a panel for the house, and a panel for the stables. Is there no disconnect switch(s) at the meter for either of those feeds? How far are those house and stable panels from the meter?

The meter can is mounted on the outside of the garage wall. There is a box next to it with the 175 amp main breaker for the stables. That goes underground 100' to the panel inside the stables. Inside the garage behind the panel is the 220V panel for the house. It has a 225 amp main breaker. It has all the breakers for anything needing 220V, stove, AC, hot water heaters, etc. It has a 100 amp breaker that feeds a subpanel 40' across the garage with all the 110V breakers.

 

[m1garand762]

Well, we have a new heat pump, I watched the tech monitor the running amps,, only about 17 amps.
The compressor is a "screw type" rather than a piston of the old days,,
The screw type should have lower startup amp demand.. no pistons to get moving,, ?

What surprises us, is that the lights will "dim" momentarily as the compressor starts.

I am wondering if I now notice this because of the new LED bulb technology, or is it an issue with my power coming from the utility?
(NOTE: We have not noticed anything else to be capable of making the lights dim)

The reason I want to blame the LED bulbs rather than the incoming power is the extreme speed that LED bulbs can respond with turn off/on.
I notice this on the taillights of cars, if the pickup has an LED third brake light, and filament regular taillights, you see the LED come on and off quickly.
The filament bulbs in the other taillights slowly come on,, then slowly turn off.

So, filament bulbs would tend to "look" like they stay on, even if the power fluctuates for a very short time.

I have checked the wire sizes, the connections, there is a new breaker installed.
I have a strange electrical service that was typical in the 1970's,,
The heat pump breakers are in their own panel, with its own main feed coming from the meter base.

The lighting that dims momentarily is connected to a separate main 200 amp panel, that is connected to the same meter base.

There is no "main" breaker in the heat pump panel, only the small 60, 30, 25 amp breakers.

If this is an issue, it seems like it must be due to the transformer servicing my house.
(I am the only one served by that transformer.)

Even if that compressor required 4X amps,, that should only be about ~70 amps,,
I would not imagine that small of a load to be able to make the lights dim??

So, if my bulbs dim on compressor startup, should that be something I investigate further,,?
or do I just learn to live with another "QUIRK" of LED lighting??

First thing it’s a scroll not a screw compressor. Screw compressors are used in chillers which you do not have. A scroll compressor is 2 interlocking plates that oscillate to compress the refrigerant. Check all of the connections all the way back to the breaker bot on the house. Do not stop at the disconnect. 25 amps is ok on 10 gauge wire . Also test the capacitor it will need to be disconnected and discharged by shorting it out the microfarad reading should be within 10 percent of what is stamped on the can. I prefer 5 percent or closer but 10 will work. Also make note of the voltage range for the capacitor it is marked on the compressor along with the microfarad. Make sure that jives with what your capacitor is a 440volt capacitor can replace a 370 but a 370 cannot replace a 440