AboutMaster Bob Expertise Master Electrician / Owner RKO Electric (USA Only) - can answer most of the typical residential, commercial and industrial electrical questions regarding new installations, wiring additions, lighting, switches and receptacle outlets and electrical upgrades of any nature.I will make every effort to respond to your questions as soon as possible at the end of the work day...very busy electrical company - your patience is appreciated. Stop by and see us at: www.rkoelectric.com
Experience Licensed Master Electrician with over 32 years licensed experience - updated with the latest NEC Codes every 3 years. Over see the daily electrical operations of two electrical companies. Also serve as a judge (for Electrical Contracting Products Magazine) to help select which new products are fit and safe for electricians and the electrical market.
Question I thought you might be able to provide some guidance on sizing and fitting an emergency electric generator to our new house. We had the house wired especially to accept an exterior plug-in portable generator. If I could fit a portable generator, it would serve dual duty on our small farm.
We live on 29 acres outside the Tulsa, OK metro area, and are not in any city limits.
When the house was finished the electrical contractor recommended a 5000 watt sizing, however I don't think he specified whether this was peak or continuous load. We wanted our emergency system primarily for winter electric outages (ice storms) which tend to cause the most collateral damage. I envision the princpal load of this equipment as Furnace blowers (we have three furnaces), Lights, Refrigerator, Attic pipes wire heater (our attic can get to freezing and we have two tankless water heaters there). Furnace, Stove, Wtr Heaters are all propane.
Here's the equipment on the back of our house - waiting for the installation of a plug-in generator. Forgive me if I don't get the equipment names just right. We have a Cutler Hammer Dbl Throw Safety Switch 100 amp 250V box, that has a short piece of conduit over to an adjacent box that contains the generator power cable. (This is the box that will have the cord and plug coiled up in it) The generator cable is stubbed out - no plug yet. It is Coleman Cable - "SEOPRENE" 105 8AWG 4/C WE00W/SCE -50oC to 105oC WTR RESISTANT P-241-3-MSHA
We've done some shopping for Generators and notice we could purchase one from the Home Improvement stores although they all have slightly different plug systems. I also spoke to "Rental Service Company" or RSC who rent generators. They could also procure a new one for me - of a brand that might be a step up from the home improvement stores.
Sorry for the long story, but I thought if you had info, it would help. I am an AllExperts volunteer too (Oil&Gas) and I know the long questions can be a pain. Anyway, thanks for any help you can offer.
Bob VR
Answer Hi Bob,
Based on the information you supplied...I fully concur with the electrical contractor....a 5 kW generator should be sufficient for the intended loads....where the larger loads are propane powered. (I cetainly know about Ice storm outages....we get our share of those here in central Maine).
When a 5kW gen is suggested...usually that refers to the rated maximum output of a generator....or what it is able to supply in a continous maximum use mode...at full output. Your suggested loads appear to be well below that level.(I say appear because you didn't state the actual power useage in amperes or watts of the loads you intend to supply)..so one rated at 5kW max should fit your needs....especially if you don't run all loads at once. Of course...you could oversize the gen (to a 6.5 or 7kw unit) to give you a little headroom...but that's not an efficient way to go in most cases...(and you would need to upgrade your #8 cord to a #6 to handle the larger supply)
It appears your DPDT safety switch (personally, I prefer an actual transfer switch set-up but your layout will work)is intended for a 30 amp 120/240 volt supply...which is typical for most back-up systems that don't require substantial power. For your lighting and fridge...and pipe heaters (are you refering to electric heat tape..?) this should be more then ample.....especially if you bring the loads up one by one...and use only the electrical power you need to be comfortable during an outage....and let the propane do the rest of the work. Be sure to shut off all unnecessary equipment and breakers during an outage..
I'm not in the habit of recommending specific brands...that's too commercialized for me..BUT - If I were to recommend a specific generator...I'd go with the brand I've had the best experince with over the 30 years in the electrical field....and that would unquestionably be the Honda line of generators. We've used them on a lot of jobsites (and other brands)....and they are by far the most reliable, efficient, user friendly and quietest running generators...when compared to other brands ....hands down....and we defintely put them thru the paces at the average constructions site...trust me.
We've used models similiar to the EM5000S the most (only the older commerical models)...and they've NEVER let us down. With the wheels and handles - They are easily moveable from place to place...can run up to 12 hours non-stop at half-load on one tank...and have ALWAYS started on first try...a VERY reliable piece of equipment...in my opinion (and most other construction workers I've talked with fully agree with me on this..) The ONLY down side is they are a little more costly then some "generic" models....but well worth the extra cost thanks to low maintenance and lost lasting value. To me...they are kind of like the "engergizer bunny"...they just keep going and going...and going. I recommend any of the Honda line generators without reservation. For more on the Honda line...and where to get them nearest you, see the EM5000S at:
You can look over the entire line at the Honda site...(they have several 5000 watt versions...even economy lines) so you may find one that better fits your needs. The dealer locator feature shows several Honda generator dealers in the Tulsa area...so you should have no problem finding one.....and shopping around for the best price.
Of course...that's just my opinion...but it's shared with so many others. You might pay a little more for them upfront....but they will provide you with MANY years of steady and reliable power....and pay for themselves many times over down the road.
Be sure the system is properly set-up and grounded...per Code. (your electrical contractor should be able to assist you in this area...your local Codes may have specific requirements - they differ from place to place)
Hope this helps...if you need more details or have new questions, please follow-up.
About Electrical Wiring in the Home
This site answers questions related to home electrical wiring, home wiring, general electrical help,and other electrical questions related to aleternating current (AC). You can find help on the National Electical Code, home electrical issues, wiring electrical outlets, installing lighting, electrical grounding, and general electrical help for do-it-yourself projects not require an electrician. If you do not see your home electrical wiring question answered in this area then please ask your electrical wiring question here
