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I have a Zinsko outdoor panel with a 100 amp breaker for the garage and 125 amp breaker for the cottage. The breakers are bad, so checked into replacing them. It seems a Zinco or Connecticut electric breaker is $175 or more each as compared to any other brand that are about $50 each.

Wondering what the difference is between these breakers and inexpensive breakers, zinas I'm contemplating replacing the panel and breakers with Siemens, Square D, etc., as panel and breakers would be $200 total. And if the breakers need to be replaced again due to being near salt water ocean, cost would be 1/3 of a $175 breaker.

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  • What is the physical size of the panel, and is this a combination meter base and disconnect unit or a standalone main panel? – ThreePhaseEel Jun 4 '16 at 19:12
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    Better yet, can you post a photo of the panel you want to replace? – ThreePhaseEel Jun 4 '16 at 20:25
  • The meter and breaker box are seperate, so it's a standalone panel about 14" high and 10" wide. Can't post a photo as the house is far away. – Bruce Jun 5 '16 at 2:24
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The reason why Zinsco/compatible breakers are so gosh darn expensive is because Zinsco panels are obsolete and have a somewhat checkered field failure history -- while they do not suffer as badly from the issues that plague FPE's line of non-breakers, the Zinsco breaker line still has some of the same problems: namely miscalibration (i.e. failure to trip under low to moderate overload conditions) and breaker-to-busbar arcing/overheating damage.

As to a replacement type: the resistance of modern electrical grade aluminum alloy (AA-8000) to salt air corrosion (pitting) is unknown, but presumed to be poor -- also, salt air and current drive can aggravate galvanic corrosion of aluminum, weighing against the use of unplated aluminum busbars in salt air, and also against zinc-plated aluminum (the standard for aluminum busbar panels) due to bimetallic effects.

This leaves us with copper busbar panel options; some use various forms of plated busbars (either silver flashed or tin plated copper), while others use a bare copper busbar. While silvered contacts are generally considered to have excellent corrosion performance overall (tarnish is conductive enough in thin layers that it doesn't impact contact performance the way oxides do), the presence of chlorides (salt spray) can result in nonconductive silver chloride being present. On the other hand, tin plating withstands salt attack very well in salt spray tests, and so does bare copper.

Another factor is that if the existing enclosure is appropriately weatherproof and in good condition, an Eaton retrofit kit can be installed by an electrician to convert the existing panel to a type CH (copper bus BR is not available in the retrofit kits). Of course, if the enclosure's shot and needs replacing, then replace it.

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Supply vs Demand

Zinsco panels/breakers are no longer manufactured because of product defect. Thus, businesses will markup the prices for them.

Replacement

Assuming the outdoor panel is your main panel, replacing the outdated, defected panel should be a relatively simple job using a modern Main Breaker panel sized accordingly.

The Utility Company can disconnect the meter for free so you or a licensed electrician can replace the panel and breakers. This is called a disconnect/reconnect panel upgrade. The Utility Co. might require a permit for reconnect. Verify this with them as to avoid any problems.

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  • He may have a meter base/main disconnect combination unit, which is significantly more challenging to replace wholesale as the utility has to fiddle with the service drop in that case... – ThreePhaseEel Jun 4 '16 at 20:09
  • Eh? The configuration it seems like he has is meter -> rule-of-six main disconnect panel with the 100A garage and 125A house breakers but nothing else (and no main breaker!) with the house and garage panels being subpanels. I just can't tell if the main disconnect panel he has is integral to the meter base or a separate unit. – ThreePhaseEel Jun 4 '16 at 20:23
  • I'm not able to take a picture, as im not at the house. The meter and panel are seperate. Service comes into the meter mounted on the garage. The outdoor Zinsco panel is located just under the meter. It doesn't have a main, just the two Zinsco breakers, one for the cottage and one for the garage.There's a sub-panel in the cottage and one in the garage. – Bruce Jun 4 '16 at 22:55
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Most 1960s era panels are still sold today (BRyant, CH, QO, GE, Murray), but FPE and Zinsco died an early death because of serious design problems that makes them unfit for continued service.

The high price of breakers isn't quality, it's scarcity. Ford Pinto parts are also expensive.

The good news is, what you have there is a meter main. It's a meter with a main breaker and a few more breaker spaces for auxiliary breakers. That's pretty easy to replace - it's impossible to de-energize, so you do need to have the service drop removed. That means you can DIY it with confidence, since it'll be fully de-energized and it will be inspected by the power company before they light it up again.

So I would junk it post-haste.

If your main panel does have a main breaker, you could eliminate the "main" part of it, and have it simply be a meter pan. Those tend to do better in the weather. Feed unbreakered hot straight into your former subpanel, then feed the garage from that. Having the breakers indoors will do wonders for their service life.

While you're at it, make sure the grounding is set up correctly. Those requirements have changed since Zinsco was in business.

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