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

[kenmac]

Did they dim with the old unit ? I have all LED bulbs, Alum. wire to my both A/C units and my led's don't dim when the unit/ units come on.
At times, Both are on at the same time.
I have a 400 amp service to my home. Alum. wire from pole to breaker box

 

[MossRoad]

...
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.

...

That doesn't sound legal/up to code/safe.

Out of the meter base, there should be a main panel first with a service disconnect, and everything else has to feed from that panel as sub-panels with isolated neutrals.

Without seeing your wiring, we only have your description to go by. Pictures worth a thousand words.

As for your flickering, I'd agree with most that say to have someone tighten everything up first and see if that takes care of it.

 

[grsthegreat]

Heat pump start up load can be very high. My old unit had 90 amp inrush, but ran at 24 amps. Lights dimmed

i added a SOFT START unit (not to be confused with a hard start kit). Problem went away. A soft starter reduced inrush loads by about 60%.

many brands out there. Mine is a sure start Made by hyper engineering

Soft Start Single-Phase | Eltwin

www.hypereng.com

 

[WM75Guy]

That doesn't sound legal/up to code/safe.

Out of the meter base, there should be a main panel first with a service disconnect, and everything else has to feed from that panel as sub-panels with isolated neutrals.

Without seeing your wiring, we only have your description to go by. Pictures worth a thousand words.

As for your flickering, I'd agree with most that say to have someone tighten everything up first and see if that takes care of it.

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.

 

[CADplans]

That doesn't sound legal/up to code/safe.

Yea, I have owned the home since it was 6 years old,,
frequently I have been told that it is not normal,,

BUT,, and it is a big BUT,, when I was having my heat pump installed, three different local county inspectors looked inside that panel.
Not one of the three mentioned "not legal" "code" or anything else.
The new heat pump has such a low amp draw, possibly moving the three circuits to the main panel is an option.

A decade or so ago, I had an electrician install a new panel, with many extra breaker locations, so it would be easy to do.

The wire feeding both panels from the meter looks to be the same size for both,,

 

[ponytug]

It is called a "line side tap" and is legal in some jurisdictions.

https://code-authorities.ul.com/wp-content/uploads/sites/4/2016/12/UL__LineSideBreaker.pdf

All the best,

Peter

 

[ljjhouser]

Just to be on the safe side - might check the ground connection in the breaker box. If the ground connection (main one that comes in with the 2 110v feeds) is not very good, that can happen. Sometimes heat is produced showing signs of a connection which is hot - discolored or melted plastic near the connection.

 

[CADplans]

As far as the lights dimming with the old heat pump,,,
the lights in question were incandescent filament bulbs,, that were changed to LED about the same time as the new heat pump installation.

They are tiny decorative "bent tip" bulbs in a hall light fixture.
I doubt that the original bulbs would have burned out in the next 10 years,,
I do not think we noticed the dimming with the old heat pump.

We changed to LED in any location that gets more than an hour a week of use.

 

[Xfaxman]

Put an incandescent back in and see if it dims.

 

[mjonesnh]

Had a similar experience as you recently. Lights blinking and fluttering with appliances and heat pump starting. Called our electric utility and they sent a crew out to check things out. Told them I thought i had a loose neutral somewhere. Pulled meter and checked connections in base. Those were fine. I pulled cover off breaker box and checked those connections. Those checked out also. They went up to transformer and replaced the 2 hot compression connectors that ties their cable to the transformer, still no change. Went back up in bucket and recrimped the original neutral connection and, bingo that eliminated the problem. so, in the end it was a loose connection on the neutral line at the pole.