Ground/neutral

[Orwell]

UK version

If you are this (U.K) side of the ocean :


Please substitute above 120V for 230V

Please substitu above 240v for 415v


You americans will be the death of us brits!

 

[gbradley]

You americans will be the death of us brits!

Ah yes! Aren't we the Red-Headed Stepchildren!

 

[Bill Simpson]

In a 120 VAC single phase line the current through line and neutral varies from max to zero at 60 Hz, but the current direction is always the same in both lines. Current doesn't flow backwards in the neutral of a properly grounded system.

If current doesn't flow both ways in a neutral can we really be talking about AC? By the way; what is forward and backwards? Left to Right? Right to Left?

 

[Tom Jenkins]

Well, Bill, I reckon backwards is bottom to top!

 

[Bill Simpson]

Tom, should of known I couldn't trip up a pro like you, but it's surprising how few people would have known the answer!

Of course it only applies to the northern hemisphere.

 

[controlsnoob]

sorry to dig up old stuff

There is a 'test bucket' at work that has a control xfmr. a suicide cord is connected to the 2ndary terms. should the bucket be grounded with the suicide cord?

 

[BobB]

Just as a matter of interest, Australia runs an MEN system. The neutral is firmly attached to ground at the entry to the premises. Further, the earth then goes to an earth stake directly adjacent to the switch board.

I guess it could be considered that ground and neutral are the same. However, ground and neutral are then run as separate entities throughout the premises. It is illegal to connect ground and neutral together except at the MEN point. It is also illegal to have more than 1 MEN point in a single distribution system.

If there are 2 distinct power entries into a premises and they are not connected to each other in ANY way, the premises would then be required to have 2 MEN points, 1 for each power entry distribution system.

 

[rsdoran]

Bob it is basically the same here, just people have a tendency to define things as they wish because the standards use a language closer to something in a legal document.

Here are some simple definitions to help out:

1. Ground: A conducting connection, intentional or accidental, between electrial equipment or circuit and earth.
2. Grounded: Connected to earth.
3. Grounded conductor: A system or circuit conductor that is intentionally grounded.
4. Grounding conductor: A conductor used to connect equipment or the grounded circuit of a wiring system to grounding electrode(s).

Some strange statements were made about neutrals, a neutral will always be a grounded conductor but not all grounded conductors are neutrals; one example is a corner grounded delta system the grounded conductor is not a neutral.

Grounding is a subject in itself, NEC and others have training classes just for this. There are EE courses for power distribution that have specialties in this area.

Anyway, like Bob said, the idea is to connect the grounding system and neutral at the supply point, after that their connecting points should never combine.

 

[PeterW]

white 'neutral' ?????? eh ?????

 

[geniusintraining]

white 'neutral' ?????? eh ?????

black 'ground' ?????? eh ?????....




Greetings Peter...

 

[504bloke]

white 'neutral' ?????? eh ?????

Strange isnt it, i thought i was going color blind all those years ago when i first came across some US equipment.

notice i spelled colour the pond side way

 

[BobB]

notice i spelled colour the pond side way

The proper way!

 

[504bloke]

I made a post here about some of the UK different supply systems and earthing arrangements for anyone that missed it.

And BobB

I thought the "Queens" english was the Proper way ?

 

[rsdoran]

I get confused about certain comments. This is an old thread and I may not have read it as close then as I am now but from the person that made this statement I am surpriesed.

In a 120 VAC single phase line the current through line and neutral varies from max to zero at 60 Hz, but the current direction is always the same in both lines. Current doesn't flow backwards in the neutral of a properly grounded system.

AC is alternating current i.e. the current does change direction, there is no backwards involved, but technically there is a polarity (magnitude and direction) change every half cycle based on the supply frequency.

What we obtain when measuring, calculating, or using an electrical charge (current) is the summation (sum) of the flow between the points of connection to the supply.

Geez guys, most you are much better at explaining this then I am.

 

[PeterW]

In the UK our neutrals have recently changed colour, due to European harmonisation.

Neutral was BLACK, now its BLUE.

Full list

----------- OLD ----------- NEW

EARTH GREEN ---------- GREEN/YELLOW

NEUTRAL BLACK ---------- BLUE

PHASE 1 RED ----------- BROWN

PHASE 2 YELLOW --------- BLACK

PHASE 3 BLUE --------- GREY.

Confusing to us oldsters.

As for earthing/neutral we have 5 types of earthing TN, TN-S, TN-C-S, TT and IT.

These are all to do where the earth/neutral originates, some from the supplier, ones a local earth probe and I believe TN-C-S is where the earth is connected to the neutral directly.

Yes I had to look these up (college seems a long time ago)

So remember, blues the new black. (white??)