Sparks from panel


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Old 08-13-18, 07:52 PM
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Sparks from panel

My son bought this old fixer-upper house with a lot of problems. Dad tried to warn him but, anyway....
He had a new 4ton A/C unit installed but when the 30A breaker, going to the condenser unit, is flipped in this panel, (which looks like one for a mobile home), sparks fly from behind it AND the breaker trips. I did a continuity check on the two wires connected to the breaker and they do not seem to be short circuited. I can understand why it is sparking because the breaker does not fit tight and the contacts are corroded really bad. But I don;t understand why a 30A breaker would trip from just a bad connection, or from being connected to a 4 ton condenser. Any ideas?

Oh yes, this panel is a "temporary" panel correct? It is powering a 100A panel on the inside wall. I advised my son to get rid of this nasty looking mess and install just an outside meter base with a 200A INSIDE panel.
 
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Old 08-13-18, 08:29 PM
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Oh yes, this panel is a "temporary" panel correct?
Are you asking us or telling us ? Something needs to be done there ASAP.

You have two items connected to that breaker. That is against code. Only one wire per screw terminal.
If the bus bars are corroded..... when the compressor draws power there is a tremendous load on the breaker and connections. If those connections are not solid.... you will get sparks and heat. The heat trips the breaker.
 
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Old 08-13-18, 09:45 PM
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No, there is only one wire on each terminal of the breaker. It may look that way in the photo.
Yes, I was asking. Should a box like this be a permanent install on the outside of a house? I guess I'm asking: should I replace this with a new box just like it? Or should I put a bigger service panel inside the house and just have a meter base outside?
 
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Old 08-14-18, 04:48 AM
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What is all the yellow/brown? Is it spray foam or have insects built a nest inside the box?
 
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Old 08-14-18, 07:52 AM
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That is not a temporary box; it's a permanent meter/main combo box which is designed for outdoor use (NEMA 3R rating). This one is passed the end of it's life due to all the corrosion and heat damage on the bus bars. My guess based on how much corrosion is visible and all the spray foam is that something up above is leaking in water (conduit/hub joint, weatherhead, split open service cable, etc) and has ruined the box. It looks like more damage than basic condensation would cause.

If he's lucky that sparking will only melt the wires off, unlucky and it's going to burn down the house. It needs to be replaced soon.
 
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Old 08-14-18, 10:07 AM
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What is all the yellow/brown? Is it spray foam or have insects built a nest inside the box?
It's spray foam. Looks nasty though.
 
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Old 08-14-18, 10:23 AM
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I just thought of something else. There is already a fairly large (30x30) workshop, connected underground to this service too. I'm thinking this 3br 3bath two story house really needs a 200amp service panel instead of this 100amp. It will be a good bit of work, but I think I will advise he call the power company to get this mess disconnected at the weatherhead, label the wires and pull the boxes, install a new meterbase, put a 200amp panel inside the house, go with a larger, copper entrance cable. Because the well, shop, condenser unit, stove, and water heater are all wired to this outside box and I would feel better if they are all inside. I hope I don't find that any of them are run under the house without conduit. What do y'all think?
 
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Old 08-14-18, 11:00 AM
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It's a reasonable guess, but the code way to figure it out is a "demand load calculation". There are a number of online calculators that can help do the math. That will tell you for sure what is the appropriate minimum service for the property.
 
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Old 08-14-18, 11:25 AM
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I just did one online and came up with over 27kw and 114 amps for the house without the 220v 100A shop panel where he will be using a welder, cooling fans, lights and other power tools
 
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Old 08-14-18, 06:16 PM
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Sparks from the bus behind the breaker is either a bad connection/bad bus, or the 4 ton was wired wrong.
 
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Old 08-15-18, 12:44 PM
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Sounds like a 150A or 200A service would be the way to go on the replacement.
 
 

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