Zinsco Electrical Panel & GTE-Sylvania-Zinsco Circuit Breakers Failure Mechanisms
by Nick Gromicko and Elise London
Here we outline the apparent failure mechanism involved with Zinsco and GTE-Sylvania-Zinsco electrical panels and circuit breakers. We include field photographs of Zinsco equipment failures from a variety of sources. This website discusses the electrical, fire, and shock hazards associated with Zinsco electrical components, circuit breakers, electrical panels, including certain Sylvania electrical panels and breakers which are in fact of the same product design and origin. Our page top photo of a burned Zinsco main circuit breaker and burned greased Zinsco electrical panel bus was provided by Washington state electrician J. P. Simmons
Our photo (left, courtesy of J. P. Simmons) shows the typical Zinsco or Zinsco-Sylvania electrical panel main bus damage from arcing.
- Arcing and/or overheating (see ZINSCO OVERHEAT IR PHOTOS), or a similar failure process occurs at the connection of the circuit breaker to the electrical panel bus damage the bus, the breaker, and the connection, making the electrical contact unreliable and leading to equipment failure.
- Circuit breakers become damaged by arcing or overheating. Damaged circuit breakers are unlikely to perform properly in response to an overcurrent condition.
- Aluminum electrical panel components appear to be an important factor in failures in this equipment
- Moisture exposure appears to be a factor in failures in this equipment.
Types of Zinsco Panel and Circuit Breaker Failures
- Circuit breakers may fail to trip in response to an overcurrent condition. This is a fire and shock risk.
- Circuit breakers may "blow out" the side casing of the device in an electrical "arc explosion"
- Circuit breakers may fail to drop power even when they are switched off [remains to be verified--DF] - that is, the breaker may appear to be switched to the "off" position but internally it may still be conducting power to the circuit.
At OK to USE ZINSCOS? we report on a different viewpoint from a vendor who continues to market this equipment and feels that at its price point in the market this product is reasonable to use, and who opines that when Zinsco equipment fails (burnups, failures to trip) it is because it was "over-used" at too-demanding an amperage draw. Our view is that it is just under that condition that a circuit breaker should trip off.
FAILURE PHOTOGRAPHS - Zinsco Sylvania Electric Panel and Breaker Field Failure Photographs
Clicking on any of the thumbnails at left will display a larger photograph.
- Zinsco electrical panel overheating (Jon Bolton) - infrared photographs - see ZINSCO OVERHEAT IR PHOTOS.
- Photo 2: A Zinsco panel bus, showing scratch and oxidation marks
- Photo 3: A Zinsco double pole breaker in-place, with the electrical panel bus exposed
- Photo 4: A Zinsco breaker side blowout, exposed breaker contact exposed in the electrical panel
- Photo 5: A Zinsco breaker side blowout-2, exposed breaker contact exposed in the electrical panel
- Photo 6: A Zinsco electrical panel bus bar burn marks, exposed by partial-removal of circuit breaker
- Photo 7: A Zinsco burned panel bus bar, blown-out circuit breaker, and arcing debris on other circuit breakers - partial disassembly
- Photo 8: A Zinsco main panel , below you can read the case report April 25, 2003 below
- Photo 9: A Zinsco burned circuit breaker , case report April 25, 2003 below
- Photo 10: A Zinsco double-pole thin style breaker, light green toggles
- Photo 11: A Zinsco copper bus bar burn, in a Zinsco electric panel using copper busses
- Photo 12: A Zinsco circuit breaker with burned contacts , closeup
- Photo 13: A Zinsco circuit breaker with burned case, closeup side view
- Photo 14: A Zinsco circuit breaker with burn and arcing flash marks, side view at the Zinsco electric panel
- Photo 15: A Zinsco circuit breaker with burned, broken case, closeup
- Photo 16: A Zinsco circuit breaker with burned, broken case , "clothes dryer quit working"
- Photo 17: A Zinsco electric panel bus details , with what looks like a circuit breaker contact trapped on the bus
- Photo 18: A Zinsco circuit breaker case damage, interior view
- Photo 19: A Zinsco circuit breaker with burn and arcing flash marks,, side view at the electric panel
- Photo 20: A Zinsco electric panel bus bar, showing pitting and burn marks
- Photo 21: Zinsco burnt up main breaker -1
- Photo 22: Zinsco burnt up main breaker -2
- Photo 23: Zinsco burnt up main breaker -3
- Photo 24: Zinsco burnt up main breaker -4
- Photo 25: Zinsco main circuit breaker and buss damage -1
- Photo 26: Zinsco main circuit breaker and buss damage-2
- Photo 27: Zinsco breaker burn marks at copper bus damage
- Photo 28: Bad copper bus damage behind a full size Zinsco breaker -1
- Photo 29: Bad copper bus damage behind a full size Zinsco breaker -2
- Photo 30: Zinsco breaker partly disassembled at site of copper panel bus damage
- Photo 31: Burned outlet, Zinsco breaker no-trip-exterior, below you can read the case report May 04, 2005
- Photo 32: Burned outlet, Zinsco breaker no-trip-interior-1, case report May 04, 2005
- Photo 33: Burned outlet, Zinsco breaker no-trip-interior-2-burned wires, case report May 04, 2005
- Photo 34: Zinsco Main Panel, case report May 04, 2005
- Photo 35: Burned outlet, Zinsco breaker no-trip-burned wall at outlet, case report May 04, 2005
- Photo 36: Burned outlet, Zinsco breaker no-trip-burned wall - 2, case report May 04, 2005
Photo 37, burned electrical wiring and receptacle, Zinsco circuit breaker did not trip.
- Zinsco failure photos #38 & 39: burned Zinsco circuit breaker, burned grey Zinsco circuit breaker with case side blowout, case reports Jeff Weissman, 3/7/2007 and 3/8/07. These photographs of Zinsco circuit breaker blowouts and bus connection burning in the Zinsco electrical panel make clear that a simple visual inspection of the panel, without disassembly, risks failure to discover damaged, unreliable components that may not be offering the overcurrent and fire protection intended.SAFETY WARNING: only a licensed, trained electrician should remove electrical panel covers or remove and install electrical components in the panel.