Grounding lug requirement

[Syahar1975]

Good evening Gents,

API 650 suggest 1 grounding lug for every 30 M tank circumference but minimum 4 lugs.

Are these 4 lugs is mandatory ?

I have a case where my 7.5 M dia, tank has 4 grounding lug but our electrical drawing shows only 2 grounding lugs is required. The grounding lug cable are connected to 2 lugs only at 180 deg apart.

Is there any other criteria to define the grounding lug quantity requirement ?

Is electrical requirement can over write the API 650 requirement ?

Your comments / advise is highly appreciated.

 

[bimr]

Yes, the electrical code will have precedence over API 650. If this is a new tank, the latest electrical code requirements will govern. If this is an older tank, the electrical code is generally grandfathered to the electrical code that was in place at the time that the tank was constructed.

 

[Syahar1975]

BIMR,

Thanks for the comments. Yes this is a new tank.

 

[valleytank]

Why is this still an issue? This just came up on AST-forum.com. Site/DEP/RMP/Purchaser/Owner etc can and will often take precedence. Don't forget the code is the bare minimum to scrape by but its based on good experience.
Whether its two or four for your tank of 24.5' OD you will be fine. But lets say for productions sake.. 2 vs 4..you may as well put 4 on because the difference will cost you peanuts. Follow 650 specs, get some 304SS lugs made up, weld them in with some 309L, LPI, be done with it. Just make sure the electrical contractor sets the grounding beds right and the paint guys leave them bare.

 

[Syahar1975]

We have install the 4 lugs in this tank based on the approved drawing.

But electrical also has approved drawing showing 2 grounding lug connection for this tank.

If we request them to put another 2 then there would be additional cost issue.

We have decided to follow the electrical approved drawing i.e. 2 connections only.