Klein v Southwire: NCVT

When we think of electrical tools you can’t help but think of Klein, they have been a household name since 1857.  Well there is a new kid on the block that has been making some waves, Southwire. Southwire offers a line of tools that rivals that of Klein, but how do they compare?


For the last year I have been using a Klein tester, the NCVT-3.  Its a feature packed model with a front facing flashlight as well as an indicator lights for varied voltage readings. Last week I picked up a new Non-Contact Voltage Tester from Southwire, their flag ship model 40150N. This little tester comes with all the bells and whistles similar to the Klein with a built in flashlight. The main difference with the Southwire is the main light is located on the rear end of the tester but it features a smaller LED on the tester tip.

Both the Klein’s and Southwire’s light share similar lumens, but the Klein is a narrow beam. In terms of flashlight use I prefer that of the Klein, but in a dark environment is just too bright while testing, Southwire did a wonderful job with the lower lumen light on the front. The Klein’s light and the Southwire’s rear facing light can be operated independently from the tester.

So whats the good the bad and the ugly?

Of the two I prefer the Klein for one simple reason, as a measurement tool it is a better meter.  The Klein gives you a more sensitive tester which will notify you with various speeds of beeping and the LED indicator for voltage. It allows you to narrow where the voltage is hot better than the Southwire. For instance on the neutral side of a receptacle with the Klein it will display a week readout where the Southwire does not activate until the hot side of it. The tip on the Klein is stubbier where the Southwire has a more traditional tip for NCVT. Both testers are IP67 rated as well.  The feel of the Southwire prevails with rubber over molding and a slightly slimmer design, but the electronics of the Klein are much more refined. Both tests will read 12-1000v, but with Southwire having a 12v button to hold down while testing lower  circuits.

Despite my preference to the Klein the Southwire is still a great tester to have in the bag, both are widely available at major box stores for $25.

Purchase the Klein NVCT at Home Depot

Purchase the Southwire 40150N at Lowes

Also available on Amazon 

This slideshow requires JavaScript.



  1. You’re right Jimbo! The Klein is fine lol. I have both testers myself and on a scale of 1-100 I give the Klein a 99 and the southwire a 95. They are both excellent tools and would be a great addition to both the pro and homeowner. Thanks 🙏🏼 for your write up. Very well done my friend 👍🏼👊🏼👊🏼

    Liked by 1 person

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s