New 200 Amp Service Mast

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  #1  
Old 10-08-11, 07:34 AM
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New 200 Amp Service Mast

I am going to install a mast for my service entrance and have a couple of questions.

I am going to relocate the overhead wire from the center of my garage to the side and the poco said the same cable will work with the new service. Do you have any suggestions how I can determine the required height of the attachment point on the mast. If I match the garage peak that would result in a 48" mast. I think it could be lower

I would also like to install the new meter box directly behind the new service panel and have the mast run up that same stud cavity on the outside of the wall. I thought securely attaching the box and building up where the mast runs through the soffitt would be more than strong enough along but the poco specs requiire two clamps attached to wall atuds along the length of the mast. If I run outside a cavity I don't have those studs and I wanted to use at least part of that cavity to run my circuits. Any suggestions?
 
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Old 10-08-11, 07:51 AM
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I would install two cross braces between the studs and use the all-thread clamps.

Mast Parts | Electrical Fittings

Your power company may have the support requirements spelled out in their design manual.
 
  #3  
Old 10-08-11, 08:13 AM
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Doyou think cross braces installed with 3.5 side against plywood sheathing would work? I will ask rep from POCO. Would make running wires inside garage easier

I was also given some straps the called cowboy straps. They attach with bolt on both sides of the clamp. Are those ok to use?
 
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Old 10-08-11, 08:44 AM
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One utility near me would not allow two hole straps. They require thru-bolts.

The cross braces may need to be cut into the studs. I would check with your power company.
 
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Old 10-11-11, 07:26 PM
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were the cross braces you were referring to metal ones? I noticed something called channel bars in the link you put in your post.
 
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Old 10-12-11, 04:43 AM
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I will check their design guide.
 
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Old 10-12-11, 09:12 AM
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You may not need to match the peak height, but you do need to have at least 12' clearance over a residential driveway at the lowest point of the service drop, and no part of the drop can be lower than 10' including the drip loop at the weatherhead.
 
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Old 10-12-11, 11:20 AM
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I can't find their design guide anymore. I would check with your power company.
 
  #9  
Old 10-20-11, 07:54 AM
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POCO Rep Just Visited

I just had a rep from my power company come out to discuss the service change and the mast.

Some questions that I had for him are what he required as far as anchoring the pole to the house and clearances. I think I am good with a 2" rigid metal conduit that rises 36" above the roof. I am allowed to anchor the service up to 30" without additional support.

He deferred the anchoring of the mast to the house to my town inspector. I realized that my original plan of using 2x4 cross bracing between studs and anchoring the mast to that may have an issue becuase the first 2x4 would be 20" above the bottom of the mast attachment to the meter box ( the new panel's flush install does not allow me to put any cross bracing until that point). There is another 30" from that brace to the top of the wall where a second brace could be installed.

Now I am wondering if I should install more 2x4 bracing behind the box. Maybe the box should not have been installed flush with the unfinished 2x4 garage wall. I could install cross bracing and also mount the service box to the 2x4 bracing.

A final question concerns the material used to connnect the meter box to the service panel. They are on opposite sides of the walls only separated by a small air gap, 1/2 inch plywood and siding ( I am going to mount the box over the dutch lap siding, but provide some plywood behind the siding to get a good strong attachment. Is grey PVC the best choice and are there any suggestions to get this setup to be waterproof? Would the meter box be grounded to the service panel?

Thanks for the great help and all the spoon feeding of information
 
  #10  
Old 10-20-11, 09:41 AM
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Originally Posted by cthomasparr View Post
connnect the meter box to the service panel. They are on opposite sides of the walls only separated by a small air gap, 1/2 inch plywood and siding
I assume you mean a back-to-back installation? You can either line them up so that one of the lower back KOs on the meter pan lines with one of the back KOs on the main panel and use a rigid close nipple; or come out the bottom or side of the meter pan with an LB fitting and then put a nipple through the wall into the back of the main panel.

any suggestions to get this setup to be waterproof?
Caulk and expanding foam if needed. Use a hole saw just bigger than the conduit so you don't have a big gap to fill.

Would the meter box be grounded to the service panel?
Yes. Use a bonding bushing on the conduit nipple. It's up to your power company's design guide whether or not the bonding bushing should be on the meter side too.
 
  #11  
Old 10-20-11, 05:40 PM
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use a rigid close nipple
Since it's a 200 amp service, I'd use a 2" nipple (O.D. of approximately 2 3/8"). Use a 2 1/2" hole saw to cut the hole and it will be a near perfect fit for a 2" nipple, you'll have very little to caulk. I'd use a bonding bushing both on the panel end and meter socket ends of the nipple as they will both be entering concentric knockouts.
 
  #12  
Old 11-01-11, 04:56 AM
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I talked with the electrical inspector in the town and I have the OK to go forward with my plans. One alteration I made was to move the panel slightly out from its recessed position between studs to mount to cross braces ( 2x4s mounted against the inside of the plywood sheathing on their wide side ). The braces would be used to also support the meter box and mast. The inspector suggested I use 2" grey pvc with terminal connectors between meter box and service panel. I will have to check that the socket depth x2 does not exceed the distance between the panels.

A final question that I have relates to the connection between the mast and meter box. The mast is threaded into a hub that is attached with four screws to the meter box. If I were to make it waterproof, I would use teflon tape on the threads and some kind of silicone on the meter box threads. Any suggestions to whether this makes sense or if there is a better way. The mast and meter box will be under a shallow soffit but will probably get pretty wet in windy weather.

thanks
 
  #13  
Old 11-01-11, 05:25 AM
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I do not believe any thing is used on the threads into a Meyers hub. My power company does not allow top entries into the socket.
 
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Old 11-01-11, 08:33 AM
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I do not use thread compound, and I think it may even be prohibited because it can interfere with grounding. The top of the hub is flared to prevent water infiltration, so I really don't think it will be a problem. You would need a very intense directed spray to get water through the hub.
 
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Old 11-01-11, 06:21 PM
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If I were to make it waterproof, I would use teflon tape on the threads and some kind of silicone on the meter box threads.
It doesn't need to be waterproof, just raintight. This conduit connection and the meter socket will never be submersed in water, but it will have plenty of rain hit it.
 
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