100A Manual Generator Transfer Switch 24000W Heavy-Duty Safety Switch

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1. Thomas H. Lawler Verified Buyer – 23 January 2025

   This switch can be used indoors or outdoors. It’ll insure you only have one power source connected to your house (or RV etc) at a time for selecting between things like utility and generators power. While manual switches like this require you to go move it (and find a flashlight to go thru the dark), it can be a lot less cost than automatic ones. The box isn’t that big and will be tight for running big wires (if needing the 100 amp size), but can also work for a 40-50 amp selection of circuits if you want. It has knock-outs on the sides and bottom of the box for your 3 cables (2 power sources and one “load” connection). Just be sure as you run the wires that they won’t be in the way for the handle to move the way it needs to.
   

2. Diane Hollo Verified Buyer – 2 March 2025

   Easy to install . Well designed
   

3. YARWELL 100A Manual Generator Transfer Switch Verified Buyer – 8 March 2025

   I’m working on a project right now; one of the things I needed was a generator cutoff box. This isolates your backup generator power source from other components of the electrical system. When I saw this heavy-duty box with a large, positive throw switch, I thought it would work. I ordered it. When it arrived, I looked it over. There were no surprises; it would do what I wanted it to do. It was made of heavy duty steel and the internals were also solid and clearly labeled. There were good instructions, too. I prepared a generator plug and cord, and then I laid out and screwed down the cutoff box and the electical panel it would attach to. Then, I started wiring it. A bit of a struggle was the knockout plugs; sometimes those can be a pain, and these were no different. The plugs can be many sizes, from small to very large. I needed the small plugs removed for romex connectors. I managed, installed the needed romex connectors, and then I inserted the wires. The box is clearly labeled for LOAD and LINE; where LINE is the power source, and LOAD goes toward the appliances. If you aren’t sure how to wire this, you can always call an electrician. After the generator wire was ready, I ran the wire to the small utility box and attached the leads to another circuit breaker; this isolates generator power from the household circuit. It’s redundant on purpose. You do not want generator power to backfeed your primary power source; you must keep them separate. This is why, in addition to the very positive large switch on this box, I also put a dedicated circuit breaker in the house box. To power the house buss bar from the generator, you have to choose to close two switches. You cannot power the household buss using your backup generator without closing these switches; therefore, you must also act to isolate grid/other power from the box by opening (turning off) the master power circuit breaker. While you can mess this up, you have to try really hard. Then, I tested the circuit with a multimeter. I closed (turned “on”) the big, orange lever on the generator control box, then I closed the 220 breaker on the house box. While my generator is 110, I used a 220 breaker on the household box so that the generator would power both legs of the buss. I tested for continuity between the plug and the buss on the household box; see my attached picture. It works. I tested all components of the system, everything worked as it should. This is a sturdy cutoff box. It is very well-made, and the function couldn’t be more obvious or positive. Recommended for electricians or knowledgable homeowners.

   

4. Garrett H Verified Buyer – 20 March 2025

   Note that I am a Licensed Master Electrician, and have dealt with more of these than most people in the non-electrical industry will ever see. That said, this is a basic 100A MTS (Manual Transfer Switch), and I see no reason that it would not work as designed. The wiring lugs are adequately sized, and all of the necessary components are isolated from each other, and the kit comes with a bonding screw, should your installation dictate you need one (not all do). The biggest thing to know about this assembly is that it carries no UL certification sticker. Does that mean that it will not work? No. Does it mean that you will fail an electrical inspection if you use it? Yes. Unless the inspector doesn’t catch it. If your project does not require an inspection, then install at your own risk, but it should work fine.