"We have used STB for over ten years for our rubber goods testing and purchasing as well as our test equipment calibration and servicing. If we have a special need or request, we know that Pat and her outstanding employees will do everything possible to get it completed and back to us. STB really is a member of the team - they are a one-of-a-kind! Thanks for all your great support over the years. 

                                                           Terry Shoemaker - Safety Director                                          Diversified Utility Services, Inc.  (San Diego)

Small Business, Woman Owned, Clearing House Certified, NFIC

DUNS #095649356, Cage Code 1DH77, SAM Registered, CA Small Micro Business #11017, CA WBE#14989, NAICS Code 334515, CDBE #14989


STB Electrical Test Equipment, Inc.  The manufacturing, repairing and testing of electrical test equipment. Nothing is more important to us than our customers' safety and satisfaction.

“This is a thank you to STB from Roseville Electric for all the help you have given us. STB manufactures top quality test equipment and we can always pick up the same day for an emergency job. They have even delivered to our site for us. Everyone is courteous and helpful. The staff at STB works hard to always provide the right equipment for the job we are doing with a positive attitude. Repair, testing and calibration of units are done and returned very quickly. They test all of our rubber goods and hot sticks. STB has tested the same day the items arrive and delivered them the next day. There is never a problem and there is no added cost for this service. Their pricing is very competitive with other companies we have used in the past but the level of service surpasses anyone else. STB proves again and again that customer service is number one priority with them.”

Gonzalo Ruiz - Senior Materials Technician

Roseville Electric

Mission: STB Electrical Test Equipment, Inc. is a premier manufacturer, distributor, and servicing facility offering personalized customer solutions for the power industry.

Vision: STB Electrical Test Equipment, Inc. will cultivate and maintain lasting customer relations through manufacturing, servicing, and distributing superior high voltage safety equipment. STB employees will always provide excellent, personalized service with honesty and integrity.

Our Mission and Vision

"I just wanted to drop you a note of thanks for your support and service. Everyone at STB has always been courteous and caring. They are knowledgeable about your products and service, always willing to go that extra mile to fill our needs. Your excellent pricing is what brought us to STB in 2002 but it’s your attention to detail and your fast turn around that keeps us returning for more. I look forward to doing business with you for many years to come."

Philis Pinkerton - Material Expiditer

Bay Area Rapid Transit


"Thank you for all of the great service you have provided us here at Henkels & McCoy here in our Pomona facility. I appreciate your willingness to help us out even when we have special requests or when we ask for things out of the ordinary. Your products and services are greatly valued by us and we again want to thank you for being a valued vendor of ours.”

Pete Block - Tool Supervisor

Henkels & McCoy (West Region)


About Us


Arnold “Stu” Stewart, original founder of STB Electrical Test Equipment, Inc., started his long career working for Western Electro Mechanical Company, “WEMCO” in Oakland. Stu was WEMCO’s instrumental technician for 23 years repairing products including phasing voltmeters, voltage detectors, ground faults, clamp-ons and phase sequence indicators. Stu was celebrated by his colleagues and customers for customizing products to customers’ requests and needs. Stu eventually began customizing his own products including custom, split core current transformers. Ultimately, Stu designed and patented his own split core, ST Model in March, 1981.


Arnold A.Stewart, Russell L. Tavare, and Kenneth Belfer incorporated STB Transformer Company, Inc. in 1979. Seeking alternate opportunities and direction, Ken Belfer and Russell Tavare left STB in 1981 and 1989 respectively. At which time, Patricia A. Tavare, Stu’s daughter, stepped in to assist her father. Pat was fully managing STB by early 1990.


Stu passed away later that year creating a woman-owned business by his widowed wife, Lois. In honor of her father, Patricia continued operating and expanding STB with her brother, Jeff Stewart.

A few years following their fathers death, Lois passed away in 2011. Jeff and Pat continued spear-heading new developments, customers and operations. Jeff relocated and sought new opportunities leaving Pat as sole owner and President of STB later the same year.

Today, STB continues to be recognized in the industry for providing top-of-the-line, quality product, personalized service and a flawless safety record. Management and staff are working diligently to further expand STB’s products and services offered.

Call Us: (530)823-5111

Call Us: (530)823-5111