Grounding the workbench

[stonky]

Newbie home stick welder here.

One subject I can't find consensus on is whether or not a workbench should be grounded, separately from the work return cable. There seems to be a huge body of people on t'internet who feel that a separate ground isn't necessary, but also a significant number who feel that it is.

Normally, I'd go with the majority viewpoint. But of particular interest is the ANSI standpoint (my bold) ...

According to American National Standards Institute (ANSI) Z49.1, "Safety in Welding, Cutting and Allied Processes," the workpiece or the metal table that the workpiece rests on must be grounded. You must connect the workpiece or work table to a suitable ground, such as a metal building frame. The ground connection should be independent of or separate from the welding circuit connection.

What's the current viewpoint here? For the people who feel it's unnecessary, I'm particularly interested in why you would disregard the ANSI point of view.

Thanks

 

[brightspark]

because the welder case its self is earthed through the mains lead .that is all thats needed on the mains voltage supply . the bad old silly days of bonding everything in site is gone now thank christ

 

[Pete.]

I just put the earth clamp on the metal bench. The ANSI requirement must have some reasoning behind it but I'm struggling to figure out what it is.

 

[brightspark]

I just put the earth clamp on the metal bench. The ANSI requirement must have some reasoning behind it but I'm struggling to figure out what it is.

the output ground is isolated from the mains input ground there is no need

 

[Robert Weaver]

Probably for if the transformer/inverter fail so they spit mains voltage down either work return or torch, an earth bonded table will cause current to trip the RCD/breaker/fuse.

 

[brightspark]

Probably for if the transformer/inverter fail so they spit mains voltage down either work return or torch, an earth bonded table will cause current to trip the RCD/breaker/fuse.

an rcd will trip without the table being bonded if there is an earth fault .they work on current imbalance no leakage to earth no trip

 

[Dave-sparks]

Whereabouts in the world are you? As you mention ANSI as your reference I assume you are in the USA?
In which case you need to check the electrical code in force in your state.

In the UK, or any other country following UK regulations, there is no need to earth/bond/whatever you want to call it, a free standing metal table.

 

[blackolive (Ste)]

because the welder case its self is earthed through the mains lead .that is all thats needed on the mains voltage supply . the bad old silly days of bonding everything in site is gone now thank christ

ATEX zones excepted

 

[brightspark]

ATEX zones excepted

wouldnt have thought he would be welding in an explosive enviroment on a bench or anywhere near unless your on the docks in turkey and torch a few thousand tonnes of nitram

 

[stonky]

Thanks for replies so far.

Whereabouts in the world are you? As you mention ANSI as your reference I assume you are in the USA?
In which case you need to check the electrical code in force in your state.

In the UK, or any other country following UK regulations, there is no need to earth/bond/whatever you want to call it, a free standing metal table.

I'm in the UK. I'm quoting ANSI because at some time someone thought that bonding the table was a smart idea; smart enough to make it a standard. I'm just trying to put that into context of what people know / do now.

Works bodies do different things in different parts of the world. If this standard originated specifically because of the supply / equipment differences in the USA then fair enough. But if it existed because someone had a different take on what was more safe, I would be interested to know why.

So I'm not so much asking from a regs point of view (although obviously I need to know what applies here in the UK), but from an electrical / safety point of view.

I've noticed that the ANSI standard is from the late 70s, so maybe thinking has just moved on from then anyway.

 

[Robert Weaver]

Presumably there's no equivalent requirement welding not on a table, ie the MK3 golf on axle stands. I've never added an earth connection when working on a car. It's not to serve a function to the welding process.
For what's it's worth, my table isn't grounded.

 

[500e]

ATEX regs are a minefield
Then you start on Employers Mutual in US

 

[stonky]

Presumably there's no equivalent requirement welding not on a table

Fair point.

For what's it's worth, my table isn't grounded.

I'm getting that general vibe from replies

 

[The_Yellow_Ardvark]

wouldnt have thought he would be welding in an explosive enviroment on a bench or anywhere near unless your on the docks in turkey and torch a few thousand tonnes of nitram

All safe now.
It all suddenly went away.

 

[mike os]

ATEX regs are a minefield

Don't even go there

 

[Dave-sparks]

Thanks for replies so far.



I'm in the UK. I'm quoting ANSI because at some time someone thought that bonding the table was a smart idea; smart enough to make it a standard. I'm just trying to put that into context of what people know / do now.

Works bodies do different things in different parts of the world. If this standard originated specifically because of the supply / equipment differences in the USA then fair enough. But if it existed because someone had a different take on what was more safe, I would be interested to know why.

So I'm not so much asking from a regs point of view (although obviously I need to know what applies here in the UK), but from an electrical / safety point of view.

I've noticed that the ANSI standard is from the late 70s, so maybe thinking has just moved on from then anyway.

USA electrical code is somewhat different and a bit backwards when compared to UK wiring regulations.

The USA also has a range of weird and wonderful supply systems, voltages and earthing methods in use.


I have no personal experience of it, but I've known industrial electricians tell tales of how badly things go if your weld current ends up returning via the electrical earth instead of the welder's ground. Suffice to say it is a situation best avoided,

 

[bricol]

18 yrs ago I was welding in several military aircraft factories in the USA - Can't recall anyone insisting any benches were independently grounded - they insisted on all sorts of other crap, but . . .

 

[stonky]

I've known industrial electricians tell tales of how badly things go if your weld current ends up returning via the electrical earth instead of the welder's ground. Suffice to say it is a situation best avoided,

That makes sense. That was the one thing that was bothering me ... what guarantee that the current wouldn't take the ground route rather than the work return.

Fairly happy now in going down the non-grounded route ... just couldn't let the idea go without airing it.

 

[brightspark]

how can the return go down the main earth when it goes through an isolating transformer both output leads

 

[bricol]

how can the return go down the main earth when it goes through an isolating transformer both output leads

When you accidently connect machine earth to the euro torch connection you just added to your Migmate . . . it worked fine for a few years until I built my new garage . . . when the power cable to my pillar drill melted . . . and then the power cable to the welder started to smell a bit warm . . .