Another master electrician claims that close nipples cannot be used in such a way. Perhaps it is because close nipples do not have tapered threads or that they do not screw in far enough to contact enough threads??????
All you have to becarefull with close nipples pipe is get correct tapered thread instead of straght cut threaded pipe that can raise some issue.
However., Both America and European both done the same thing for very long time and no issue arised with this and just heed with bonding issue if your local area do required it.
Merci,Marc
