Masonry Box: Weather Resistant?

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Old 06-08-11, 03:12 PM
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Masonry Box: Weather Resistant?

This relates to another thread in the forum. When placing a masonry box in a concrete block wall exposed to the elements does it need to be weather proof. My Googeling only shows masonry boxes that don't appear to be weather resistant.
 
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Old 06-08-11, 03:30 PM
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Yes it would need to be weatherproof if exposed to the elements. I'm not sure that anyone makes a box that is both approved for embeddment in masonry and weatherproof. I can't imagine how the covers could seal properly even if the box was sealed. A die cast bell box surface mounted on the masonry would be a much better solution. I guess you could half-embed a bell box, leaving it a bit proud of the surface leaving enough room to get the right cover on it and giving nearly the appearance of a recessed outlet.
 
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Old 06-08-11, 04:43 PM
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Thanks. Just wanted to see if I was missing something.
 
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Old 06-08-11, 05:51 PM
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It seems to me that if the galvanized masonry box was installed flush in the wall with the proper weatherproof covers on it, it wouldn't be exposed to the elements. If it were exposed to the elements, it wouldn't be approved because it has knockouts and not threaded hubs. This is done all the time on masonry exterior building walls such as found in schools and shopping centers.
 
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Old 06-08-11, 06:27 PM
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When the concrete wicks in water, it will corrode the box as well as the alkalinity in the concrete which will help speed up corrosion.
 
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Old 06-09-11, 08:56 AM
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In this case it was a block landscaping wall, so the inside and outside of the wall would be exposed to the elements.
 
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Old 06-09-11, 05:32 PM
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That would be different then. There is nothing typical about a landscape wall. My comments were intended for a typical masonry building wall.
 
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Old 06-09-11, 05:35 PM
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Originally Posted by Justin Smith View Post
When the concrete wicks in water, it will corrode the box as well as the alkalinity in the concrete which will help speed up corrosion.
That's why masonry boxes are generally made from galvanized steel.
 
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Old 06-09-11, 07:13 PM
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That's why masonry boxes are generally made from galvanized steel.
I had to work on a box the other day in masonry installed in'72 that was very rusty. It was just a typical handy box, which I think are galvanized.
 
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Old 06-10-11, 05:33 AM
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It is quite possible that the handy box was just stamped steel.
 
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Old 06-10-11, 04:20 PM
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Originally Posted by Justin Smith View Post
I had to work on a box the other day in masonry installed in'72 that was very rusty. It was just a typical handy box, which I think are galvanized.
EMT is galvanized too, but it rusts very easily when exposed to corrosive elements. Masonry boxes are galvanized, but it is different galvanizing process than a typical handy box (which may or may not be galvanized) or EMT. I can't explain it, but there is a difference in galvanizing processes.
 
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Old 06-10-11, 04:36 PM
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I can't explain it, but there is a difference in galvanizing processes.
I can't either but I suspect it is electro galvanized vs hot dip galvanized. The latter probably being a thicker coating.
 
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Old 06-10-11, 06:26 PM
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I also saw some handy boxes and bx installed in the 1930s in an amusement park in damp locations which looked pretty new, and only rusted around the knockouts. So, what is the difference in galvanizing processes in masonry versus handy boxes?
 
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Old 06-10-11, 06:30 PM
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Hot-dipped leaves a fairly thick coating of zinc to protect the steel. Electro-galvanizing is zinc plated to the steel and may be only a few molecules thick. Electro-galvanized can easily be scratched through the zinc leaving the steel unprotected.
 
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Old 06-10-11, 06:52 PM
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So, then the masonry boxes must be hot dipped, while handy boxes are electro-galvanized. That makes sense, as the masonry boxes get exposed to corrosives, while handy boxes only get exposed to dry air.
 
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