Generator - Cummins 20kw Help!

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Location
California
Occupation
Electrician
I did alot of generac installs however i took on a cummins 20kw thinking it would be simple connections like in the generac.. I need help with the connections on the low voltage wires. If anybody that has done these can give me hand that would be great!

Confirm I need a dedicated 120v 20A circuit to generator?
Also, 9 TB low voltage wires #1-9 do they connect to the same exact number #1-9 on the transfer switch?
 

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
The first two Cummin's I did were a piece of cake, then they decided to change everything! There are a couple of different transferswitches they use now, and you have to figure out which one you have, to find the wiring diagram that goes with it. The new ones have an aluminum enclosure and are louder than the old ones. That was the nice thing about the old ones, they were quieter than the Genercraps.
 

kwired

Electron manager
Location
NE Nebraska
I did alot of generac installs however i took on a cummins 20kw thinking it would be simple connections like in the generac.. I need help with the connections on the low voltage wires. If anybody that has done these can give me hand that would be great!

Confirm I need a dedicated 120v 20A circuit to generator?
Also, 9 TB low voltage wires #1-9 do they connect to the same exact number #1-9 on the transfer switch?
Can't confirm for your unit, but seem to recall having to run a 120 volt circuit to some units in the past that typically supplied power for a battery charger and engine block heater, where one is needed. They weren't necessarily cummins units, definitely was not typical generacs that are targeted for dwellings either though. This was separate circuit and isolated from starting and transfering controls which usually were derived from the normal feed to the transfer equiment and/or from the 12VDC starting/engine controls system.

Guessing that since it is a 20 kW unit it is big enough engine it is not air cooled, making the engine block heater more likely unless not to be used where it gets really cold.
 

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor

Bill Barclay

New User
Location
Spicewood TX
Occupation
Engineering technician
I did alot of generac installs however i took on a cummins 20kw thinking it would be simple connections like in the generac.. I need help with the connections on the low voltage wires. If anybody that has done these can give me hand that would be great!

Confirm I need a dedicated 120v 20A circuit to generator?
Also, 9 TB low voltage wires #1-9 do they connect to the same exact number #1-9 on the transfer switch?
Did you ever get the dc wiring figured out? I am having the exact same issue. I need the TB4 Connector to the generator set connection. The 9 wires from the ATS to generator. Very confusing.
 

Knuckle Dragger

Master Electrician Electrical Contractor 01752
Location
Marlborough, Massachusetts USA
Occupation
Electrical Contractor
I did alot of generac installs however i took on a cummins 20kw thinking it would be simple connections like in the generac.. I need help with the connections on the low voltage wires. If anybody that has done these can give me hand that would be great!

Confirm I need a dedicated 120v 20A circuit to generator?
Also, 9 TB low voltage wires #1-9 do they connect to the same exact number #1-9 on the transfer switch?
I've down a few in the last couple of years.
Yes, you do need a dedicated 120 volt circuit out the the genset.
No.
 

Knuckle Dragger

Master Electrician Electrical Contractor 01752
Location
Marlborough, Massachusetts USA
Occupation
Electrical Contractor
I found the control leads confusing to look at (all the same color "white") Although they are labeled. Some are labeled for multiple uses so they have multiple numbers and letters on them. So you have to pay attention.
Feel free to message me if you still need help. I might be able to help you fill in the blanks.
 

Highlife24

New User
Location
Louisiana
Occupation
Electrician
So I was looking at this forum for the answer to the original question which was really never answered. I have the rs20ac generator with the ats that comes with it [new style]. I have a 120vac circuit for my battery charger. Not my problem. The problem is the low voltage connections. Any idea what needs to be done to finish this installation?? All I have going to my generator from my ats at the moment is 3-#12 wires for the battery charger and then the 3-2/0 wires that feed my panel when using the generator. Any help is greatly appreciated. Thanks!
 
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