On the covered Kohler standby generator, MainPwrOverL means shutdown. Main power overload — an overcurrent (short-circuit) fault on the controller output. First, leave the set off and do not reset repeatedly. Then: contact an authorized dealer for service. Leave the set off and do not reset repeatedly.
Differential
Likely causes of “Kohler standby generator code MainPwrOverL”, and how to tell them apart
- 1
The generator shut down because of a main power overload (MainPwrOverL)
What separates it The set stops and the controller shows the message
How to confirm Leave the set off and do not reset repeatedly
- 2
An overcurrent on the controller output
What separates it A short circuit in the load
How to confirm Disconnect loads
- 3
Too much connected load
What separates it Many appliances were running at once
How to confirm Reduce the load
- 4
A wiring fault in the home
What separates it A circuit has a short
How to confirm Have an electrician check
- 5
A controller fault
What separates it The load is light and the fault returns
How to confirm Call an authorized dealer
Before you touch a setting
Record this first — changing settings destroys the evidence
- Whether the controller shows MainPwrOverL straight after starting or only once loads are connected
- Which large loads were running, such as the air conditioner, the well pump and the electric range
- Whether the main breaker on the generator or the transfer switch has tripped
- The generator model and serial numbers from the label
Try in this order
0 of 9 completedWhat to do first
ReversibleLeave the set off and do not reset repeatedly.
Correct only the documented fault domain
ReversibleContact an authorized dealer for service.
Leave the set off
ReversibleKohler's guidance is to leave the set off and not to reset it repeatedly, since each restart can repeat the overcurrent.
Disconnect large loads
ReversibleSwitch off large appliances such as the air conditioner, the electric range and the water heater, to see whether the load caused the overload.
Look at the breakers
ReversibleCheck the generator's breaker and the home's transfer switch for a tripped breaker, and note which circuit tripped.
Ask an electrician to check for a short
ReversibleAn overcurrent on the controller output can mean a short circuit in the load, so have an electrician check the circuits.
Contact an authorized Kohler dealer
ReversibleThe table says to contact an authorized dealer for service, and the dealer can read the controller's fault history.
Restart only when cleared
ReversibleDo not restart the generator until the cause has been found, and then bring loads on gradually.
Write down what was running
ReversibleList the large appliances that were on when the set shut down. The dealer can then judge whether it was a genuine overload or a fault in the output circuit.
Model-specific
What is true of this model and not of its siblings
- The message on this page
- MainPwrOverL, a main power overload.
- Parts involved
- The controller output and the load.
- Source
- Kohler Power's residential generator controller guide.
- Overload and overcurrent
- An overload means the generator was asked for more power than it can give, while an overcurrent can also come from a short circuit that draws a very large current very quickly. The controller protects the generator in both cases by shutting it down, which is what MainPwrOverL reports.
- Bringing loads on in steps
- After a repair, start the generator and add loads one at a time, starting with the largest motors. Starting everything at once can trip the controller again, even when nothing is wrong with the set.
- Standby generators and large loads
- A home standby generator can start large motors, but only within its rating. The air conditioner, a well pump and an electric range starting together can exceed it, and the controller shuts the set down to protect it. A load-shedding or a load-management module on the transfer switch can sequence the loads so that this does not happen.
- Ask the dealer about load management
- If the overload follows a particular appliance, ask the dealer about a load management module or a soft-start kit for the air conditioner. These reduce the starting current, which can be the difference between a set that carries the house and one that trips.
Stop boundary
When this stops being a self-service repair
- !Contact an authorized Kohler dealer, as Kohler directs, and have the controller's fault history ready
- !Do not repeatedly reset the generator, since each restart can repeat the overcurrent
- !Disconnect the loads at the transfer switch before any further start-up
Evidence ledger
Sources behind this answer
Exact questions
Common questions
What does MainPwrOverL mean on a Kohler standby generator?+
Shutdown. Main power overload — an overcurrent (short-circuit) fault on the controller output.
Can I reset it?+
Do not reset repeatedly.
Can I run the generator with fewer loads?+
Only after the cause has been found, and then add loads gradually.
Does a service contract help?+
An authorized dealer with a contract can respond faster and read the controller's history.
Can a generator that is too small cause MainPwrOverL?+
Yes, a set that is smaller than your loads will trip when they start together, and the dealer can size it.
Does the controller keep a fault history?+
Yes, and the dealer can read it, so note when the fault occurred.