Open Circuit or High Resistance - THE GREAT DEBATE

[Foxhound]

A class of thirty students are presented with a question for there level 3 class assignment.

L1 AND L1 = 2 Ohms
N1 AND N1 = 2000 Ohms
E 1 AND E1 = 2 0hms

29 of them say open circuit on the neutral.
1 says it is a high resistance fault because it is a finite reading and there for it can not be open circuit but a poor termination due to the fact a reading has been obtained.

Who is right? The mob or the guy who is about leg it to the car park?

You decide his fate ...

(loser gets a free back door pass for the Blue Oyster bar)

 

[Guest154]

someone posted this yesterday prob one of ur class mates

 

[KAS1]

I would say it needs investigating further before drawing any conclusions,

 

[Guest154]

lol just read ur other post

 

[Foxhound]

I would say it needs investigating further before drawing any conclusions,

You should be a politician

 

[JulianC]

Hope you made it safely to the car park. 2000 ohms isn't, never has been and never will be an open circuit. If it was, I could have saved myself a fortune (well, a few quid) replacing resistors with fresh air back in my electronic engineering days.

 

[snowhead]

If it was 30 experienced electricians answering a question (NOT THIS QUESTION) and 29 said 1 thing, 1 said different, it's most likely the 29 would be correct and the 1 would be wrong.

In this case it's 30 non experienced electricians.
Of the 29, the majority have probably conferred and got the answer wrong for the same reason, whereas the 1 sought outside help and got it correct.

 

[Foxhound]

Hope you made it safely to the car park. 2000 ohms isn't, never has been and never will be an open circuit. If it was, I could have saved myself a fortune (well, a few quid) replacing resistors with fresh air back in my electronic engineering days.[/QUOTE

Thanks mate,

Just to be more clear it up this is a ring circuit and I'm assuming it depends on the meter yo are using. Some meters will read O/R or O/L and some say 2000 ohms which can be assumed to be a open circuit. It's a bit confusing

 

[snowhead]

Some meters will read O/R or O/L and some say 2000 ohms which can be assumed to be a open circuit. It's a bit confusing

It's not confusing, it's a hyperthetical question and you are being presented with the test results of 2000ohm.
For this question it doesn't matter what meter was used.

A more advanced question might present varying readings gained from various meters and ask you to explain the problem

 

[telectrix]

if your meter had read >2000 ohms, that would mean that it was outside the range of the meter and could then be either open or high. the answer is then to use a meter with a higher upper read limit.