Complete Guide to Buying a Transfer Switch for Your Generator

When it is time to purchase a transfer switch for your generator or battery inverter system, there are several key factors to consider before pushing buy. This guides walks you through everything you need to know to make the right purchase. 

Do You Know Your Neutral Type?

Understanding the neutral configuration of your generator or battery inverter is extremely important. Do you have floating neutral or bonded neutral?

This is important because of the National Electrical Code (NEC) requirements, which ensure proper neutral bonding and electrical safety. Getting it wrong can create unsafe conditions or damage your system. 

Note: Not all transfer switches can accommodate both bonded and floating neutrals

Types of Transfer switches:

There are two primary categories of transfer switches, ATS and MTS. 

ATS -Automatic Transfer Switch 

• Automatically transfers power to and from the grid. 
• No human interaction required. 
• Most expensive option. 
• Ideal for whole-house systems or critical infrastructure.

MTS – Manual Transfer Switch  

• The user manually switches between grid and generator power. 
• More affordable and simple to install. 
• Great for residential and small commercial applications. 

Both ATS and MTS styles are available in:

• NEMA 1: For indoor use 
• NEMA 3: For outdoor installations
  

Options for your transfer switch to energize:

Ratings both Voltage and Amperage

Every transfer switch must be rated equal to or greater than the load you are supplying for both Amperage and Voltage

Note: Your power supply should be 125% rating of your load in watts

Testing Lab Approval:

This is perhaps the most important factor, every transfer switch must be tested and approved as a ‘whole unit”. Individual parts combined to make one approval, that approval number is UL 1008. UL is the most recognized standard used. 

There are 20 testing labs in the USA,  ETL (Intertek), MET , UL are just 3 examples. All labs assign a number that is associated with the company. In the case of transfer switches, you would see: UL1008 and a company number 5xxxxxxx10.

This number allows the consumer to check for forged labels, which are very common for overseas imports. Elimination of all testing and quality control.

Choosing the right transfer switch isn’t just about price. More importantly, it is about safety, compatibility, and code compliance. By understanding your power source’s neutral type, choosing the appropriate switch category, and ensuring proper certification, you will be set up for a reliable and safe power transfer during outages. 

Questions? Check out our FAQ page today.