Load Management with Generac Generator

Status
Not open for further replies.

mkgrady

Senior Member
Location
Massachusetts
I am going to feed a 200 amp residential panel with a 20 KW generator. Three large loads will be controlled with DLM modules. In addition I need to feed a 100 amp subpanel that is fed from this same 200 amp panel. I plan to use the priority one 120 volt output to control a 100 amp contactor with a 120 volt coil. A DLM module is only good for switching 50 amps. The actual normal load on this circuit is normally just a few amps and occasionally bumps up to maybe 30 amps when drying clothes, but I can't use a relay that is rated less that the circuit feeder. What have others used in a case like this?

Most relays or contactors I've seen that can handle this load are three phase and VERY expensive and they don't come with an enclosure.

In case you are wondering the subpanel feeds a few lights and bedroom receptacles plus an electric clothes dryer and a steam unit. The steam unit has not been used for several years but the owner does not want it disconnected.
 

tomlounge

New User
Location
Norcross, Ga
Generac DLM's

Generac DLM's

I am going to feed a 200 amp residential panel with a 20 KW generator. Three large loads will be controlled with DLM modules. In addition I need to feed a 100 amp subpanel that is fed from this same 200 amp panel. I plan to use the priority one 120 volt output to control a 100 amp contactor with a 120 volt coil. A DLM module is only good for switching 50 amps. The actual normal load on this circuit is normally just a few amps and occasionally bumps up to maybe 30 amps when drying clothes, but I can't use a relay that is rated less that the circuit feeder. What have others used in a case like this?

Most relays or contactors I've seen that can handle this load are three phase and VERY expensive and they don't come with an enclosure.

In case you are wondering the subpanel feeds a few lights and bedroom receptacles plus an electric clothes dryer and a steam unit. The steam unit has not been used for several years but the owner does not want it disconnected.

Is it possible to install the DLM on the 50 amp steamer circuit itself and leave the sub panel alone?. Since you say the sub panel does not present a very large load, this would be my strategy. FYI: Generac has discontinued the use of the 120v DLM's and is now using a 'PMM' which allows you to use low voltage control wiring between the transfer switch and PMM (We use thermostat wire)...Good luck!!
 

mkgrady

Senior Member
Location
Massachusetts
Is it possible to install the DLM on the 50 amp steamer circuit itself and leave the sub panel alone?. Since you say the sub panel does not present a very large load, this would be my strategy. FYI: Generac has discontinued the use of the 120v DLM's and is now using a 'PMM' which allows you to use low voltage control wiring between the transfer switch and PMM (We use thermostat wire)...Good luck!!

I don't think I can get a control circuit to the steam circuit so no I will need to find a reasonably priced 100 amp contactor to control the entire subpanel. I saw that Grainger has one for about $1,700 without an enclosure.... yikes!

I'm happy to hear Generac is changing the load managemnt modules (50 amp relays) to a low voltage coil. Running 600 volt wire to them has been a pain.
 

curt swartz

Electrical Contractor - San Jose, CA
Location
San Jose, CA
Occupation
Electrical Contractor
Don't base prices on Grainger. They are about 10X the price of an electrical wholesaler on most items.

Would you be using a normally closed contactor or normally open? If you are going to use a normally open contactor the customer may not be very happy about the noise level since most of them are not very quiet and it will be energized most of the time.
 

mkgrady

Senior Member
Location
Massachusetts
Don't base prices on Grainger. They are about 10X the price of an electrical wholesaler on most items.

Would you be using a normally closed contactor or normally open? If you are going to use a normally open contactor the customer may not be very happy about the noise level since most of them are not very quiet and it will be energized most of the time.

Good point. Ill figure out a way to use normally closed
 

goldstar

Senior Member
Location
New Jersey
Occupation
Electrical Contractor
There's a company named PSP Products that make the contactor you're looking for. I have a PDF cut sheet on my computer of it but Forum rules won't allow me to post it here. I've tried going to their website www.pspprocucts.com but it's not listed there (must be a new product). If you want the info send me a PM with your e-mail address and I'll send it to you.

Or, you can contact the company direct :

PSP Products, Inc.
8535 Phoenix Drive,
Manassas VA 20110
Phone: 800-648-6802
www.pspproducts.com

Product is :
1100DF1208-1-10R
2-100 Amp Relays NEMA3R Enclosure
 

Greg1707

Senior Member
Location
Alexandria, VA
Occupation
Business owner Electrical contractor
50 amp breaker

50 amp breaker

Since you mentioned the load on the 100 amp subpanel is low, why not change the breaker feeding the subpanel in the main panel from 100 amps to 50 amp?
 

mkgrady

Senior Member
Location
Massachusetts
Since you mentioned the load on the 100 amp subpanel is low, why not change the breaker feeding the subpanel in the main panel from 100 amps to 50 amp?

They want to maintain the ability to operate a steam unit which is fed with a 2 pole 40 from the remote subpanel. They have no plans to use the steam unit but when I suggested disconnecting it they said they want to keep it connected as a future selling feathure of the house
 

SceneryDriver

Senior Member
Location
NJ
Occupation
Electrical and Automation Designer
AutomationDirect sells a contactor that would work:

http://www.automationdirect.com/adc...ctors_-z-_Overloads/105_to_150_Amp/SC-E5-100V

They're 3-pole units; just use the outer two poles. They shouldn't buzz too much either, since the coil is actually DC - incoming AC power is run through an internal bridge rectifier before going to the coil.

AD also stocks and sells Hubbell enclosures at very good prices.


SceneryDriver
 
DLMs, ATS and extended service

DLMs, ATS and extended service

We use Fuji contactors from AD. BTW I think the DLMs are only 40 amp for resistive loads.

Slightly off topic. We are frequently running into generator installs on residences with meter mains using feed-through lugs to an extended service. What I would like to do is feed the line side of the ATS from the feed-through lugs on the meter main and then feed the load side of the ATS to the line side of an SE rated LC that also has feed-through lugs. I would then feed the existing extended service from the feed-through lugs on the new Load Center. Am I able to do this code-wise and if so would it be 3-wire all the way to the extended service or would everything past the ATS be treated as sub-panels with 4-wire bonding and grounding rules. This is a 200a single phase system and all panels are 200a.

Thanks in advance.
Pat...
 

mkgrady

Senior Member
Location
Massachusetts

mkgrady

Senior Member
Location
Massachusetts
We use Fuji contactors from AD. BTW I think the DLMs are only 40 amp for resistive loads.

Slightly off topic. We are frequently running into generator installs on residences with meter mains using feed-through lugs to an extended service. What I would like to do is feed the line side of the ATS from the feed-through lugs on the meter main and then feed the load side of the ATS to the line side of an SE rated LC that also has feed-through lugs. I would then feed the existing extended service from the feed-through lugs on the new Load Center. Am I able to do this code-wise and if so would it be 3-wire all the way to the extended service or would everything past the ATS be treated as sub-panels with 4-wire bonding and grounding rules. This is a 200a single phase system and all panels are 200a.

Thanks in advance.
Pat...

I believe the generac dlm modules are rated 50 amps resistive and 40 amps inductive.
I don't really follow your question but everything downstream of a meter/main needs a seperate neutral and grounding conductor.
 
Status
Not open for further replies.
Top