useless college lecturers

[andy]

started college again... unfortunatly. anyway, he drew this on the board (obviously his version on the board looked a little better than my quick version)

the socket is metal and there is a fault, where the live has touched the case. Mr. bloggs touches the socket.

will he get a shock? most people say yes, some say no. (i said no).

he then goes on and on and asks why he wont get a shock. say because at no point is the neutral connected to earth so there isnt an earth path and he says thats wrong.

then, after 15 minutes, he then syas he wont get a shock because the transformer isnt earth and there is no path for the current to flow! (and he used pretty much the exact words that i had used, yet i was wrong?)

****in idiot.

and people why i hate college...

/rant

 

[Carloss]

Yes he will get a shock.. unless mr bloggs is made of rubber? if you touch live you will get a shock... he may be refereing to an earthing arrangement with the neutal?

to prevent this from happening we use RCD's/mcb's.... but one thing i don't understand... why does he use a transformer on a ring/radial cct?

this reminds me when i was at college... hated it, i have used 2% of what i learned at college working as a spark.....

which college do you go to?> watford?

carloss

 

[andy]

Yes he will get a shock.. unless mr bloggs is made of rubber?

to prevent this from happening we use RCD's.... but one thing i dont understand... why does he use a transformer on a ring cct?

this reminds me when i was at college... hated it, i have used 2% of what i learned at college working as a spark.....

which college do you go to?> watford?

carloss

how can he get a shock when the transformer IS NOT EARTHED.

i should have said it a bit better: transformer is at substation, fuse is at CU. its a fairly basic digram.

if the transformer was earth, then he would get a shock

and i go to a college in the north east

 

[Carloss]

As far as i know... if you touch live no matter what you will get electricuted. However if there is no earth then the rcd will not opperate so you will keep gettin electricuted untill the breaker cuts out or someone turns it off same applies with neutral i think.
correct me if i am wrong.

How old are you andrew?

carlos

 

[BJS_Spark]

All substation transformers will have a connection to earth unless something has gone wrong. So what is his point?

 

[Spark123]

Electrical separation will mean he does not get a shock, unless another mr bloggs on another phase touches live, or there is a fault causing either of the two other phases to earth or neutral to earth. The definition "transformer needs to be earthed" is not 100% correct, the star point of the transformer needs to be earthed hence TN (Terra neutral) as in TN-S / TN-CS.

 

[andy]

As far as i know... if you touch live no matter what you will get electricuted. However if there is no earth then the rcd will not opperate so you will keep gettin electricuted untill the breaker cuts out or someone turns it off same applies with neutral i think.
correct me if i am wrong.

How old are you andrew?

carlos

you cna only get a shock if you are earthed. go to the nearest rail line and hang form the overhead supply. you wont get a shock because there isnt a path form the overhead line to earth. same here. there is no earth=no shock
as for neutral: you dont get a shock form that because its at the same potential as earth. neutral is infact a live conductor. called neutral tho because its at the same voltage as 'earth'

All substation transformers will have a connection to earth unless something has gone wrong. So what is his point?

this is just a exercise diagram, as tho the transformer didnt have an earth connection. i.e isolation transformer. you touch 1 side, unless the other side is 'earthed' then you dont get a shock

Electrical separation will mean he does not get a shock, unless another mr bloggs on another phase touches live, or there is a fault causing either of the two other phases to earth or neutral to earth. The definition transformer needs to be earthed is not 100% correct, the star point of the transformer needs to be earthed hence TN (Terra neutral) as in TN-S / TN-CS.

finally. someone with a brain.

 

[Carloss]

**** u

 

[Spark123]

At least something stuck in from my 2381 course

 

[ban-all-sheds]

**** u

What was the point of that?

You wrote something wrong, and Andrew corrected you. He did not abuse or ridicule you, and yet you respond like that.

You've not been posting here very often of late - I suggest you increase your periods of silence until you have learned to be civil.

 

[Carloss]

Sorry.

I tried to explain what i though the answear was.. and the bit about no brains got my back up.... i only tried to help.

Anyway. Thanks for correcting me.

BAS.. you ever see posts from Albert or FWL?

Carlos

 

[andy]

Sorry.

I tried to explain what i though the answear was.. and the bit about no brains got my back up.... i only tried to help.

Anyway. Thanks for correcting me.

BAS.. you ever see posts from Albert or FWL?

Carlos

take away an earth path=no electric shock

 

[ban-all-sheds]

BAS.. you ever see posts from Albert or FWL?

Yes, but not recently...

 

[securespark]

As far as i know... if you touch live no matter what you will get electricuted

Try going up to the first floor of a domestic dwelling (wooden floor) and undo a light switch. Next, with your bare fingers, touch the common live feed (and nothing else). Tell me, do you feel anything?

I don't, because I am not connected to earth.

 

[Carloss]

hmmm, i see what you mean...

What about the resistance in your body.....? say i had moisture/wet hands.. i would still not get a shock?


While i am here... just done 2nd fix in a kitchen today.. the fuseboard was very very neat.. however there was no RCD just a main isolator (tnc-s earthing system ) and BS1362 breakers ... does this mean a certificate cannot be issued becuase it does not meet the requirements? if so should i put a small contactum board next to it with an rcd + breakers and then tap into the main fuseboard and use a 60A breaker? This is cheaper than saying to customer they need a new fuseboard...then have to do test+inspect on all circuits (part P comes in)blabla... whats your opinion on this?

carloss