InspectAPedia®   -   Search InspectApedia

Bulldog pushmatic circuit breaker labeling (C) InspectApedia.com Bulldog & ITE Pushmatic Circuit Breakers
Bulldog Electrical Panel Design & Patent History

Bulldog Pushmatic Circuit Breaker patent disclosure history & design features:

This article provides key patents describing the design of the Bulldog & Pushmatic circuit breaker & panel and the features of those components

The article series discusses the history of Pushmatic breakes, gives advice to homeowners whose building is served by a Pushmatic electrical panel, and we discuss both compatability of and concerns when using replacement circuit breakers or used Pushmatic circuit breakers sold by salvage operatoers.

We solicit field failure and field inspection reports of questionable or possibly problematic electrical equipment in buildings such as the Bulldog™ and ITE-Pushmatic® brands described here.

Page top photo: a Bulldog Pushmatic™ circuit breaker showing typical labeling and certifications, contributed by an InspectApedia reader Heather in 2018.

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

Bulldog & Pushmatic Patent Disclosure & Design Features

Pushmatic panel label (C) Daniel FriedmanThe original Bulldog Pushmatic electrical panel produced by the Bulldog Electric Products Co. was purchased by ITE(Gould) in 1976 and subsequently purchased from ITE by Siemens Electcric (ca 1984).

Bulldog / Pushmatic electrical panels were manufactured in the U.S. as early as 1930 and were installed in U.S. homes as residential electcrical panels principally between 1950 and 1970.

Below are Bulldog and Bulldog Pushmatic breaker and panel patent disclosures that give complete details of the history of the product and its features, but of course those documents do not discuss Bulldog / Bulldog Pushmatic / ITE Pushmatic / ITE Gould Pushmatic failures and hazards.

Watch out: A particular Pushmatic hazard we have observed is breaker internal jamming such that when the breaker was pushed to switch to the OFF position the breaker remained "ON" internally, risking fire or fatal electcrical shock to building occupants or to electrical workers. It is opined by some electricians that because the breakers were "grease fed" a "lack of maitnenance" over time led to the jamming or made the breakers "difficult to operate".

The circuit breakers also lack an internal magnetic trip mechanism that is considered a safety feature and that is widely used in many other circuit breaker designs. Instead the breaker relies solely on an internal thermal trip mechanism, typically a bi-metallic spring.

Other Pushmatic hazards included a design that made it too easy for DIY'ers to tap a circuit directly onto the panel's bus bar without proper overcurrent protection, and a failure to perform reliably when installed outdoors.

Really? Mainteance? Owners of residential buildings never perform maintenance and rarely even examine their electrial panels and circuit breakers.

OPINION: as a building contractor performing electrical work, later as a home inspector, later as a researcher and journalist, I was disappointed to have to tag Pushmatic panels as "unsafe" (they are) because physically the original equipment was in my view built with high quality materials and workmanship. And other electcricians cited the reliability of a bolt-on load center that was a design not used in other less-costly electrical panel brands.

However the very real safety hazards of Pushmatics derive from a combination of design and age and are at the very least documented in field reports presented in this article series.

For that information in more-detail see PUSHMATIC - BULLDOG PANELS

Bulldog Electrical Product Co. & Bulldog Pushmatic Patent History

This patent history, roughly in order from oldest to newest, gives both product and feature historical details of the Pushmatic circuit breaker and panel design and ownership.

Bulldog Panel design 1947 (C) InspectApedia.com Bulldog Panel design 1947 (C) InspectApedia.com

Illustration: Platz - Bulldog Electric Products Co. panelboard with detachably mounted electrical devices, US Patent 2,428,320 Sept. 30, 1947, illustrates the characteristic "Bulldog Pushmatic" circuit breaker panel design. Cited below on this page at year 1947.

Bulldog Pushmatic Electric Products Patents

US2424909 * 30 Dec 1942 29 Jul 1947 Frank Adam Electric Co
See FRANK ADAM ELECTRICAL PANELS
Circuit interrupting device
US2439511 * 10 Apr 1944 13 Apr 1948 Frank Adam Electric Co Latching or tripping mechanism of circuit breakers
US2447652 * 30 Oct 1942 24 Aug 1948 Westinghouse Electric Corp Circuit breaker
US2459427 * 24 May 1945 18 Jan 1949 Fed Electric Prod Co Circuit breaker
US2491088 * 29 Sep 1945 13 Dec 1949 Essex Wire Corp Thermal-magnetic circuit breaker
US2573306 * 11 Aug 1948 30 Oct 1951 Gen Electric Electric circuit breaker
US2579673 * 27 Sep 1947 25 Dec 1951 Square D Co Circuit breaker
US2588497 * 10 Dec 1949 11 Mar 1952 Westinghouse Electric Corp Circuit breaker
US2590663 * 3 Feb 1950 25 Mar 1952 Westinghouse Electric Corp Circuit breaker
US2624815 * 7 May 1945 6 Jan 1953 Westinghouse Electric Corp Circuit breaker
US2624816 * 9 May 1945 6 Jan 1953 Westinghouse Electric Corp Circuit breaker
US2631208 * 19 Apr 1951 10 Mar 1953 Gen Electric Electric circuit breaker
US2673263 * 18 May 1951 23 Mar 1954 Gen Electric Thermomagnetic electric relay
US2696540 * 27 Jan 1950 7 Dec 1954 Fed Electric Prod Co Automatic circuit breaker
US2696541 * 19 Feb 1953 7 Dec 1954 Bulldog Electric Products Co Circuit breaker
US2716679 * 11 May 1954 30 Aug 1955 Wadsworth Electric Mfg Co Circuit breaker
US2738393 * 12 Mar 1952 13 Mar 1956 Cutler Hammer Inc Circuit breakers and the like having power elements
US2824191 * 5 Feb 1953 18 Feb 1958 Fed Electric Prod Co Circuit breakers
US2866036 * 30 Nov 1955 23 Dec 1958 Crabtree & Co Ltd J A Electric circuit breakers
US3278707 * 22 Oct 1964 11 Oct 1966 Gen Electric Circuit breaker with ambient-temperature compensating means

Additional Bulldog & Pushmatic Circuit Breaker & Panel Patent Disclosures

1952 Bulldog Electrical Panel using ITE Circuit Breakers

1952 Bulldog Controls Electrical Panel installed in a Delaware home (C) InspectApedia.com RT

Special thanks to an anonymous InspectApedia.com reader who has provided these photographs of a 1952 Bulldog Electric Panel. The main breaker appears to be a Pushmatic circuit breaker, but the individual circuit breakers are marked as an ITE product. This 200-Amp electrical panel is installed in an older home in Wilmington, Delaware.

1952 Bulldog Controls Electrical Panel installed in a Delaware home (C) InspectApedia.com RT

Above: a Pushmatic-type main breaker in this 1950s Bulldog Controls brand electrical panel.

Below: ITE-circuit breakers in the same electrical panel

1952 Bulldog Controls Electrical Panel installed in a Delaware home (C) InspectApedia.com RT ... 1952 Bulldog Controls Electrical Panel installed in a Delaware home (C) InspectApedia.com RT


...

Continue reading  at PUSHMATIC BREAKER FAILURE REPORTS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

Suggested citation for this web page

BULLDOG PUSHMATIC DESIGN HISTORY at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to ELECTRICAL INSPECTION & TESTING

Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia

Ask a Question or Search InspectApedia

Try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.

Search the InspectApedia website

Note: appearance of your Comment below may be delayed: if your comment contains an image, photograph, web link, or text that looks to the software as if it might be a web link, your posting will appear after it has been approved by a moderator. Apologies for the delay.

Only one image can be added per comment but you can post as many comments, and therefore images, as you like.
You will not receive a notification
when a response to your question has been posted.
Please bookmark this page to make it easy for you to check back for our response.
Our Comment Box is provided by Countable Web Productions countable.ca

Comment Form is loading comments...

Citations & References

In addition to any citations in the article above, a full list is available on request.



ADVERTISEMENT