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-   -   LB or Elbow (http://www.diychatroom.com/f18/lb-elbow-5669/)

LAR234 01-02-2007 03:43 PM

LB or Elbow
 
What is the proper use of a L-body and a 90 degree elbow? I know a L-body is used for wire pulls and cannot have splices in them. I recently had an electrician do some work in my garage and he recommended that I change the conduit from my house to the air conditioner compressor. I presently have a 90 degree elbow at the corner of the house and at the entrance to the house. Should I change these to a L-body?

Thanks.

Christopher 01-02-2007 04:22 PM

LAR234,

Any given conduit run between box access is limited to four bends (360 degrees). Any more can result in undue stress on wire installation. The L-Body provides a 90 degree turn and the origin of a new run which can contain four more bends. L-Bodys are also useful where there isn't room for a typical bend radius.

As for HVAC equipment, many locals require that the conduit terminate on the building exterior in a disconnect switch close enough to the unit to connect the equipment with a piece of liquidtite.

...Christopher

LAR234 01-02-2007 09:02 PM

LB or Elbow
 
Christoper, all your infomation is correct, but I'm still not sure about the use of the 90 degree elbow. The electrician said the fittings on my installation are incorrect. The total length of the conduit is about 5 feet. The conduit leaves the junction box with a 90 degree sweep and then outside with a 90 degree elbow, 8 inches straight conduit followed by another 90 degree elbow at the corner of the house, and then terminates at a quick disconnect box. I purchased 2 Carlon E986 to replace the metal version of the E990 elbow but I am curious to know why the elbows are incorrect. Thank you for your reply.

Christopher 01-03-2007 09:32 AM

LAR234,

As long as you are using metal fittings with metal conduit and plastic fittings with PVC conduit, I don't see any problem in what you have described.

Remember that PVC conduit runs require a ground wire which is best to originate at the main circuit breaker panel.

...Christopher

jwhite 01-03-2007 04:28 PM

Unless you have a problem accessing the cover, or you want to make a splice, you can use either the LB or elbow.

LB's that are marked with their cubic inch capacity can be used to make a splice as long as they are treated as a juction box with regard to box fill. Elbows are never large enough to splice.

smokumchevy 01-03-2007 10:58 PM

Is it possible that he was simply refering to the elbow sweeps not hugging the corner and the house exit enough making it suceptable to damage or improper support?

Its kind of difficult to comment on description alone without pics. Perhaps you should contact him and ask him to explain his concern.

-Greg

LAR234 01-05-2007 07:30 AM

LB or Elbow
 
Thanks to everybodys reply. I am going to replace the EMT with PVC and use LB's instead of elbows and add a ground wire between the junction boxes.


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