ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat Box
Recent Posts
Unusual Well Pump Switch Failure
by sabrown - 10/28/20 04:31 PM
Look at this mess...
by InspectorE - 10/27/20 09:09 PM
New tool
by gfretwell - 10/24/20 11:09 AM
Where is Everyone?
by Bill Addiss - 10/17/20 07:04 PM
New in the Gallery:
Facebook follies, bad wiring
FPE in Germany pt.2
Who's Online Now
0 registered members (), 21 guests, and 17 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Transformer Bonding #112926 11/30/01 01:21 AM
Joined: Oct 2000
Posts: 3,631
Admin Offline OP
Administrator
Member
[Linked Image]
Quote
I removed this transformer today. It was a pretty good installation if you can see through the dust. A couple things puzzled me though. The primary is the conduit on the right. The installing electrician ran the EGC from this conduit through the lug on the grounding bushing. Then he took it unspliced through a lug on the neutral bus and onto a lug on the case. I assume he was trying to establish a bonding jumper. Nice try! Not how it is done. Not to mention the conductor was only a #6 when a #2 is required. (the phase conductors are #4/0) There is a factory installed copper bonding strip that runs from the case to the neutral bus. I can only assume this was the bonding jumper. I haven't seen a transformer with this strip going to the XO. Only the coil frame. (BTW this one goes to the frame too) Not having the original installation instructions I can't be sure if this strip qualifies as a bonding jumper for this transformer.
What do you think?

- Nick

Tools for Electricians:
Re: Transformer Bonding #112927 11/30/01 08:18 AM
Joined: Mar 2001
Posts: 2,056
R
Redsy Offline
Member
Nick,

Is the secondary neutral connected directly to a grounding electrode, or just to the primary EGC ?

Re: Transformer Bonding #112928 11/30/01 09:53 PM
Joined: Aug 2001
Posts: 599
N
Nick Offline
Member
The secondary neutral is connected to the grounding electrode. You can see the GEC coming in from the right, it is properly bonded then runs directly to the XO bus. It terminates just to the left of the blue C phase conductor.

Re: Transformer Bonding #112929 11/30/01 11:08 PM
Joined: Mar 2001
Posts: 2,056
R
Redsy Offline
Member
Got it. It looked like only a lug.

Re: Transformer Bonding #112930 12/01/01 11:07 PM
Joined: Oct 2000
Posts: 2,721
Scott35 Offline
Broom Pusher and
Member
Not really within the scope of your questions / comments of this post, but I was just pondering the Manufacturer's choice in the Parallel Secondary Windings on a somewhat small Transformer.
This looks like a 75KVA Transformer.

My views here do not reflect anything more than just why the coils were wound Parallel for a semi-small power rating. But then again, I have seen some really large and complex Transformer cores!
Maybe I am Jaded [Linked Image]

As far as the Grounding goes, I like the fact that the Installing Electrician included the Primary circuit's EGC, but as Nick has said, the #6 bond to the GES for this Transformer's Secondary is insufficiently sized.

I'll probably catch he** from the Inspectors in the forum here, but it looks like someone dropped the ball when this was Inspected!
I say this because all the Transformers I've done, the dead-front covers were left off until Inspection was done [card signed].
If this was done by me, it would have been caught by the Inspector and the good 'ol Non Compliance / correction card comes out!
On the other hand, maybe this was overlooked.

Maybe I'm a show-off [Linked Image], I just want the Inspectors to be able to see something that has been done with an "Artistic" approach, which might never be seen again by another person.
BTW, It's always nice to hear an Inspector say "Look At That Nice Work", since it's hardly ever heard from anyone else [Linked Image]

Scott SET


Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!
Re: Transformer Bonding #112931 12/02/01 12:58 AM
Joined: Aug 2001
Posts: 599
N
Nick Offline
Member
Good guess Scott. It is a 75KVA!

Re: Transformer Bonding #112932 12/02/01 02:06 AM
Joined: Oct 2000
Posts: 2,721
Scott35 Offline
Broom Pusher and
Member
I got it right?!!!? Finally! [Linked Image]

Thanks for the message, Nick.

Scott SET


Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!

Featured:

2020 National Electrical Code
2020 National Electrical
Code (NEC)

* * * * * * *

2020 Master Electrician Exam Preparation Combos
2020 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
watersparkfalls
watersparkfalls
Washington...Not DC
Posts: 236
Joined: March 2005
Show All Member Profiles 
Top Posters(30 Days)
Popular Topics(Views)
271,060 Are you busy
205,042 Re: Forum
193,167 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.3