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Generac Guardian™ 20kW Aluminum Home Standby Generator

Generac Guardian™ 20kW Aluminum Home Standby Generator
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Model: 5887
(Based on expert analysis, manufacturer ratings and customer reviews)
4.8 out of 54.8 out of 54.8 out of 54.8 out of 54.8 out of 5
Number of Reviews (14)
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  • Product Description
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  • 19
    Product Q&A
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Product Description
+
Grade
Style
Run Watts
20,000
Rated Watts
Voltage
120/240 Single-Phase
Fuel
Engine
Grade
Emergency
Style
Standby (Air Cooled)
Run Watts
20,000
Voltage
120/240 Single-Phase
Fuel
LP/Natural Gas
Engine
Generac OHVI


Product Video Disclaimer: "PED is not responsible for any variances from the product in this video and the item you purchase. Please review all product specs prior to purchase."

Features
Features
  • Fully Automatic Operation When Paired With Nexus Smart Switch™
  • Generac OHVI Air-Cooled Engine
  • Features plateau honed cylinder walls and plasma moly rings
  • Full pressure lubrication system w/ 2 year oil change interval
  • Aids in cooling the engine for longer life
  • Operates On Clean Burning, Efficient Natural Gas or LP (Vapor)
  • Skewed Rotor Design For Smooth Output Waveform "Clean Power"
  • Automatic voltage regulator equipped for +/- 1% regulation
  • Nexus™ Digital Controller Monitors & Controls All Functions
  • Provides system status - compatible with Nexus™ wireless monitors
  • Sound Attenuated Weather Proof Enclosure
  • Attractive styling with lockable acess doors
  • Incorporates electrostatically applied epoxy paint technology
  • Sound dampening enclosure limits sound pressure to a low 66dB(A)
  • Matching fascia kit and 1' flexible fuel line included
  • Built-in Battery Charger (Battery Sold Separately)
  • Automatic Transfer Switch - ATS (Sold Separately)
  • Customize your system based on your actual application
  • Select the ideal ATS & DLM™ modules for load shed capabilities
  • Listed to UL2200 Engine/Generator Standard for Safety
Specifications
Product Specs
Voltage
120/240 Single-Phase
Frequency
60 Hertz
Rated Watts
20000 Watts
Surge Watts
20000 Watts
Fuel Type
LP/Natural Gas
NG Power Capacity
18000 Watts
LP Power Capacity
20000 Watts
NG Fuel Consumption @ 50% Load
206 ft³/hr
LP Fuel Consumption @ 50% Load
1.89 gallons/hr
Rated Amps
83 Amps
Decibel Rating @ 7m Learn More Sound levels are measured in decibels (dB). The lower the decibel rating, the less noise the product makes. As an example, a ticking watch is 20 dB while on the other end of the scale, a lawn mower is around 90 dB.
66 dbA
Transfer Switch
Automatic (Not Included)
Battery
Not Included (525 CCA)
Enclosure
Aluminum
A/C Ton Rating
5-Tons
Mounting Pad
Composite (Included)
Cooling System
Air Cooled
UL Listed
Yes
Grade Type
Emergency
Engine
Engine Brand
Generac OHVI
CC
999 CC
Consumer Engine Warranty
3 Years
Commercial Engine Warranty
3 Years
Engine RPM
3600 RPM
Low Oil Alert/Shutdown
Yes
Overview
Weight
451 Pounds
Made in USA
Yes
Consumer Warranty
3 Years
Commercial Warranty
3 Years
Product Style
Standby Generator
Product Length
48 Inches
Product Width
25 Inches
Product Height
29 Inches
UPC
696471058871
Grade
Style
Run Watts
20,000
Rated Watts
Voltage
120/240 Single-Phase
Fuel
Engine
Grade
Emergency
Style
Standby (Air Cooled)
Run Watts
20,000
Voltage
120/240 Single-Phase
Fuel
LP/Natural Gas
Engine
Generac OHVI


Product Video Disclaimer: "PED is not responsible for any variances from the product in this video and the item you purchase. Please review all product specs prior to purchase."

Features
Features
  • Fully Automatic Operation When Paired With Nexus Smart Switch™
  • Generac OHVI Air-Cooled Engine
  • Features plateau honed cylinder walls and plasma moly rings
  • Full pressure lubrication system w/ 2 year oil change interval
  • Aids in cooling the engine for longer life
  • Operates On Clean Burning, Efficient Natural Gas or LP (Vapor)
  • Skewed Rotor Design For Smooth Output Waveform "Clean Power"
  • Automatic voltage regulator equipped for +/- 1% regulation
  • Nexus™ Digital Controller Monitors & Controls All Functions
  • Provides system status - compatible with Nexus™ wireless monitors
  • Sound Attenuated Weather Proof Enclosure
  • Attractive styling with lockable acess doors
  • Incorporates electrostatically applied epoxy paint technology
  • Sound dampening enclosure limits sound pressure to a low 66dB(A)
  • Matching fascia kit and 1' flexible fuel line included
  • Built-in Battery Charger (Battery Sold Separately)
  • Automatic Transfer Switch - ATS (Sold Separately)
  • Customize your system based on your actual application
  • Select the ideal ATS & DLM™ modules for load shed capabilities
  • Listed to UL2200 Engine/Generator Standard for Safety
Specifications
Product Specs
Voltage
120/240 Single-Phase
Frequency
60 Hertz
Rated Watts
20000 Watts
Surge Watts
20000 Watts
Fuel Type
LP/Natural Gas
NG Power Capacity
18000 Watts
LP Power Capacity
20000 Watts
NG Fuel Consumption @ 50% Load
206 ft³/hr
LP Fuel Consumption @ 50% Load
1.89 gallons/hr
Rated Amps
83 Amps
Decibel Rating @ 7m Learn More Sound levels are measured in decibels (dB). The lower the decibel rating, the less noise the product makes. As an example, a ticking watch is 20 dB while on the other end of the scale, a lawn mower is around 90 dB.
66 dbA
Transfer Switch
Automatic (Not Included)
Battery
Not Included (525 CCA)
Enclosure
Aluminum
A/C Ton Rating
5-Tons
Mounting Pad
Composite (Included)
Cooling System
Air Cooled
UL Listed
Yes
Grade Type
Emergency
Engine
Engine Brand
Generac OHVI
CC
999 CC
Consumer Engine Warranty
3 Years
Commercial Engine Warranty
3 Years
Engine RPM
3600 RPM
Low Oil Alert/Shutdown
Yes
Overview
Weight
451 Pounds
Made in USA
Yes
Consumer Warranty
3 Years
Commercial Warranty
3 Years
Product Style
Standby Generator
Product Length
48 Inches
Product Width
25 Inches
Product Height
29 Inches
UPC
696471058871
Product Specs
+
Specifications
Product Specs
Voltage
120/240 Single-Phase
Frequency
60 Hertz
Rated Watts
20000 Watts
Surge Watts
20000 Watts
Fuel Type
LP/Natural Gas
NG Power Capacity
18000 Watts
LP Power Capacity
20000 Watts
NG Fuel Consumption @ 50% Load
206 ft³/hr
LP Fuel Consumption @ 50% Load
1.89 gallons/hr
Rated Amps
83 Amps
Decibel Rating @ 7m Learn More Sound levels are measured in decibels (dB). The lower the decibel rating, the less noise the product makes. As an example, a ticking watch is 20 dB while on the other end of the scale, a lawn mower is around 90 dB.
66 dbA
Transfer Switch
Automatic (Not Included)
Battery
Not Included (525 CCA)
Enclosure
Aluminum
A/C Ton Rating
5-Tons
Mounting Pad
Composite (Included)
Cooling System
Air Cooled
UL Listed
Yes
Grade Type
Emergency
Engine
Engine Brand
Generac OHVI
CC
999 CC
Consumer Engine Warranty
3 Years
Commercial Engine Warranty
3 Years
Engine RPM
3600 RPM
Low Oil Alert/Shutdown
Yes
Overview
Weight
451 Pounds
Made in USA
Yes
Consumer Warranty
3 Years
Commercial Warranty
3 Years
Product Style
Standby Generator
Product Length
48 Inches
Product Width
25 Inches
Product Height
29 Inches
UPC
696471058871
Reviews
(14)
+
Generac Guardian 5887 Reviews & Ratings
100% of Reviewers Recommend This Product
Product Q&A
(19)
+
Search Product Q&A's Answered by Jared, the Generator Expert
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WHAT IS THE MANUFACTURERS INSTALLATION GUIDELINE FOR A 20 KW GENERAC GENERATOR AWAY FROM COMBUSTIBLE MATERIAL (WOOD FENCE)?
DOUG FINLEY  
from Oklahoma 
March 22, 2013
Answer
NFPA 37 Standards for the installation of stationary combustion engines and gas turbines, states that this distance should be at least 5 feet from any combustible material. Some local codes can be more strict so check with your local inspectors or AHJ (Authority Having Jurisdiction).
+
Could you tell me what size LP tank I would need for a 20kW Generac Home Standby Generator? Could I use two tanks or one big one?
John Dimsdale 
from North Carolina 
February 06, 2013
Answer
The minimum LP tank size recommended by Generac would be 200 Gallon depending on the ambient temperature in your area.

It is a good idea to contact your local LP supplier and let them know that you will be installing one of these units that have a BTU rating of 294,000 BTU/HR and they can help you properly size it based on your specific location.
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Does the 5870 construction (enclosure make up) meet NFPA 37 condition 2 requirement?
Bob 
from New Jersey 
October 02, 2012
Answer
Subsection 4.1.4 of NFPA 37 reads as follows:

“4.1.4 Engines Located Outdoors. Engines, and their weatherproof housings if provided, that are installed outdoors shall be located at least 1.5 m (5 ft) from openings in walls and at least 1.5 m (5 ft) from structures having combustible walls.
A minimum separation shall not be required where the following conditions exist:

(1) The adjacent wall of the structure has a fire resistance rating of at least 1 hour.
(2)* The weatherproof enclosure is constructed of noncombustible materials and it has been demonstrated that a fire within the enclosure will not ignite combustible materials outside the enclosure.”

A4.1.4 (2) Means of demonstrating compliance are by means of full scale fire test or by calculation procedures.
Because of the limited spaces that are frequently available for installation, it has become apparent that exception (2) would be beneficial for many residential and commercial installations. With that in mind, the manufacturer contracted with an independent testing laboratory to run full scale fire tests to assure that the
enclosure would not ignite combustible materials outside the enclosure.

Per Generac Owner's Manual (All 8, 10, 14, 17 & 20kW Air Cooled Automatic Standby Generator):

The criteria was to determine the worst case fire scenario within the generator and to determine the ignitability of items outside the engine enclosure at various distances. The enclosure is constructed of non-combustible materials and the results and conclusions from the independent testing lab indicated that any fire within the generator enclosure would not pose any ignition risk to nearby
combustibles or structures, with or without fire service personnel response.

Based on this testing and the requirements of NFPA 37, Sec 4.1.4, the guidelines for installation of the generators listed above are changed to 18 inches (457mm) from the back side of the generator to a stationary wall or building. For adequate maintenance and airflow clearance, the area above the generator should be at least 4 feet with a minimum of 3 feet at the front and ends of the enclosure.
This would include trees, shrubs and vegetation that could obstruct airflow. See the diagram on the installation drawing within the owner’s manual on under the specs link for details.

Generator exhaust contains DEADLY carbon monoxide gas. This dangerous gas can cause unconsciousness or death. Do not place the unit near windows, doors, fresh air intakes (furnaces, etc.) or any openings in the building or structure, including windows and doors of an attached garage.
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Do I need the battery to run the unit or does one come with it? Anyway, is it needed for it's operation?
Woody 
from Georgia 
August 11, 2012
Answer
A battery is required to start the generator at time of power loss. The unit does not come with a battery and one will need to be purchased separately.
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What is the difference between the 5875 and the 5887?
Joe DiPietro 
from Ohio 
July 07, 2012
Answer
Joe, the 5875 basically includes the smart circuit automatic transfer switch, which you'll need to operate the generator.

The 5887 is just the generator - no transfer switch. It is usually purchased if you already have a transfer switch or if you need a different transfer switch for a unique installation.
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Jim, what is the phone# where I can order a 20KW Generac propane generator w/transfer switch? Can I pay by check? Somewhere I saw "Save 2% by paying with check". Is this true?
Fran Downing 
from Minnesota 
May 08, 2012
Answer
You can either place your order online by adding item# 5875 to the cart and following the checkout procedure or contact customer support at 877-437-7998 and one of the CSR's can assist with placing your order. The following link takes you to the product page:

Model 5875

We do offer pay by check with a 2% savings, you would need to mail a paper check and when the check is received by our accounting department you will be notified via email.

From date of email notification we hold the order for 5 business days and then process and ship the order on the 5th day. See our check policy below:

Pay By Check Policy
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How is the battery charged on these 20 kW air-cooled Generac generator? Does 120V need to be provided out to the generator in order to power a battery charger? Thanks!
Tim Vitanza 
from Pennsylvania 
January 30, 2012
Answer
The generator has a built in charger inside of the generators Nexus controller and when properly connected a 120V wire from the ATS (Automatic Transfer Switch) goes to the generator which provides the needed power for the internal battery charger.
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What would cause the Generac 20kw guardian air cooled unit to fluctuate voltage under load?
Brian 
from New Jersey 
January 17, 2012
Answer
If the unit goes beyond the maximum of 82A the voltage can drop. The maximum surge amperage of the 20kW is 145A with a 30% voltage drop.

If you are having voltage issues well under the 82A range you need to have a Generac service tech inspect the unit.

Service Center Search
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I've just ordered from you a 5887 w/out transfer switch but just noticed 92% buy the 5875 w/switch. I have a geothermal home that has a 50amp circuit breaker(uses 42amps). my electrician recommended the 5887. Could I use the 5875?
Richard Ramondetta 
from Connecticut 
January 14, 2012
Answer
The generators are exactly the same except that one comes with a switch and one does not. It really depends on if the generator has enough output to cover your Geo-thermal system "at start-up" and everything else you would have running on the generator at the same time.

Your electrician should be calculating your starting loads to verify what you can and cannot run. Plus the prepackaged system comes with a whole house type switch which may not work with your specific application based on your wattage needs with the Geo system.

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Does this model have a built in battery charger?
Don 
from New York 
October 24, 2011
Answer
When properly connected to a Generac transfer switch the internal battery charger in the generator Nexus controller will keep the starting battery charged.
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what size pipe for 20kw model 5875 connecting to lp or ng
Mario Deramo 
from New York 
September 27, 2011
Answer
Mario,

The 20kW unit has a 1/2" pipe connection but, the pipe run diameter is based on the distance from the fuel source.

Minimum pipe size - 1" - with max distance 20 ft
- 1-1/4" with max distance 130 ft
- 1-1/2" with max distance 305 ft
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For a 20 KW nat gas unit which brand to you recommend and why? For use in Dallas. Thanks Jim
Jim 
from Texas 
August 19, 2011
Answer
I highly recommend the Generac model 5875 as Generac has the newest technology and the best engine in the industry with their OHVI Industrial engine. This engine is the only one that is specifically designed for generator use and is built in Wisconsin. The most environmentally friendly generator on the market - consumes less fuel and releases fewer emissions. Generac is the number 1 selling generator in the US.

Generac 20kW Model 5875
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Jim I have a 100 amp Pre-Nexus service rated transfer switch. Can I use this with a nexus generator? Ive heard there is some special wiring for the battery charger to work
Mike Noonan 
from Michigan 
April 18, 2011
Answer
There is a special kit that needs to be added to the switch to accept the 120V connection which provides the power to the internal generator controller for the charger. These kits are available from your local Generac dealer - Part Number: 0H93030SRV.


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How long can the 20kw propane generator run continuously?
Alan Marcet 
from California 
February 13, 2011
Answer
These units are designed for emergency back up to lost utility power and if you lose power for an extended amount of time these units can handle running for weeks if necessary. Please note that these units are not designed to run as a primary power source and if installed in this capacity the warranty will be void.

Generac does offer one primary power/off the grid type standby generator which is model 5818 and is specifically designed for extremely long run times.

Model 5818 EcoGen
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How far does a generator has to be from my house?
Jim 
from Massachusetts 
February 04, 2011
Answer
The manufacturer recommends the back side of the unit to be set no less then 18 inches from any non-combustible surface and the sides of the unit need at least 36 inches for proper intake and exhaust.

Note: It is recommended to check with your city, county and state codes as they may differ from the manufacturers recommendations.
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What are the BTU requirements for the Generac 20kW Standby Generators?
Rich 
from Oregon 
January 29, 2011
Answer
The BTU requirements can be found in the owner's manual which is listed in the specs tab. For the 20kW Generac Standby unit the BTU requirement is 294,000 BTU/HR.

Owners Manual
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What kind of oil comes in the generator, and when it is time to change it? Can I run Mobile 1 Synthetic 5W30 year round in central Oklahoma?
Ron Hopper 
from Oklahoma 
January 24, 2011
Answer
The Generac standby generators are shipped with 5W30 oil in them and Generac does give the option to use 5W30 Synthetic in needed. The owner's manual covers all oil options and temperature ranges. Oil changes are determined by use and maintenance is also covered in the manual.

Owners Manual
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I noticed that Kohler states you do not need a concrete pad when using their composite shell generator. My question is; does the same go for the Generac model 5875? Can the transfer switch that comes with model 5875 be substituted for a 100A transfer switch? Thank you, Kevin Acres Electric Corp.
KEVIN BESANCON 
from Florida 
January 21, 2011
Answer
Generac states that you can use pea gravel as a sufficient base for their standby generators 8kW to 20kW.

To be able to substitute the transfer switch Generac offers the generator alone under model 5887 and a suitable transfer switch can then be purchased separately.

Generac 5887
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Hi Jim, I live in Alaska and own a 5875 20KW Home standby Generac. I need to get a cold weather kit. I am looking at the Generac Cold Weather Kit for 14-20kW Home Standby Generators (992/999cc). First, is this the correct product for my generator and second, is it a "plug and play' install? I understand I will need to change the oil to synthetic 5W30 so my guess is I'll need a maintenance kit as well. The generator has less than 3 hours on it. Many thanks, - Bill Thomson
Bill Thomson 
from Alaska 
January 21, 2011
Answer
That is the correct cold weather kit for the Generac Guardian 20kW model 5875 (or 5887) and it is a plug and play type unit, however, it is recommended by Generac to have a certified electrician install it due to the high voltage connection.
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