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Zinsco Circuit Breakers
Summary: Learn about Zinsco Circuit Breakers which are used in some home electrical panels and understand why some of these circuit breakers have had problems.
© By: Dave Rongey
Types of Zinsco Circuit Breakers
Zinsco circuit breakers are still found in many home electrical circuit breaker panels. The Zinsco brand had it's share of problems and still do for some electrical services that may have the older aging twin or tandem Zinsco circuit breakers.
The problem of a weakening connection to the main electrical panel buss, especially if the panel buss bar has any irregularities. This can be a problem with the higher amperage twin circuit breakers, yet even the larger full size Zinsco breakers may encounter a problem with the main panel buss bar.
One replacement for Zinsco circuit breakers is the Sylvania brand.
The Most Common Types of Zinsco Circuit Breakers in Home Electric Panels
30 Amp Breakers
Here are three types of 30 Amp Zinsco circuit breakers: A Full size 2-pole 240 Volt, a 1-pole or single pole, and a twin size 120 or 240 volt circuit breaker.
Types of Zinsco Breakers
This variety of different types and sizes of circuit breakers are commonly found in a Zinsco home electrical panel. The twin style circuit breakers are used when space becomes limited and 2-pole or 240 volt circuits need to be connected.
Wire Terminals of the Breaker
The wire or conductor terminal connections of these zinsco circuit breakers are shown to demonstrate the different sizes of screw drivers that are required to fasten the wire into place. The medium size straight slot screw driver that can be used for the full size circuit breakers cannot be used on the small twin style zinsco circuit breakers.
Installing Zinsco Circuit Breakers
Explanation of contact surface points as they relate to the panel bus.
Contact Surfaces of the Breakers
The contact surfaces of these three styles of zinsco circuit breakers are shown here to help understand the smaller contact surface of the twin style circuit breaker on the far right. This smaller contact surface is why some of the larger amperage twin circuit breakers could have problems.
Comparing the Breaker Contact Surface
If the larger contact surface of the full size Zinsco circuit breakers looses its tension strength or the circuit breaker is not installed correctly then this could result in arcing due to a poor connection. Older Zinsco circuit breakers can now be replaced by the Sylvania brand which may offer a better connection with the panel buss bar. Some of these circuit breakers have there contacts coated with a corrosion inhibitor ointment which will help prevent oxidation of the contact surfaces.
Electrical Wiring with Zinsco Breakers
Question: I am hooking up a tanning bed. According to the instructions, It operates from a 220 AC source. It requires a 6-20R outlet and a dedicated 20 amp circuit.
The R series matches the other skinny or twin breakers already being used. Inside the panel I connected the bare copper wire to the ground bar and the white and black to the breaker. After hooking everything up and turning on the tanning bed, one side of the breaker trips after about 10 seconds. I am starting to wonder if the breaker is wrong. I am thinking its not an actual 2 pole breaker, but a twin single pole. this would make a difference, right? Tim.
Answer: Hi Tim - Great Question!
NOTE: This question is based on a specific project. Ask The Electrician provides help for your electrical project: Ask Electrical Questions