1st week at college 16th edition .... question?

[steveg1957]

Which one of the following is an extraneous conductive part?

a)The metal case of a gas cooker
b)The metal case of an electric cooker
c)The steel housing of a transformer
d)The metal frame of an electric fire

Which is correct and why?

I cant decide between the gas cooker or transformer ..... HELP!

 

[andy]

Which one of the following is an extraneous conductive part?

a)The metal case of a gas cooker
b)The metal case of an electric cooker
c)The steel housing of a transformer
d)The metal frame of an electric fire

Which is correct and why?

I cant decide between the gas cooker or transformer ..... HELP!

ask your lecturer. the whole point of the course is that you can find the info from OSG/regs on your own. when your on site, you can rely on other to help you

 

[Spark123]

Definition:
Extraneous conductive part. A conductive part liable to introduce a potential, generally earth potential, and not part of the electrical installation.

Exposed conductive part. A conductive part of equipment which can be touched and which is not a live part but which may become live under fault conditions.
(equipment meaning electrical equipment)

You need to ask yourself, is the body of a transformer an exposed conductive part or an extraneous conductive part, similarly is a gas cooker an exposed conductive part or an extraneous conductive part?

 

[ban-all-sheds]

It would be nice if they told you whether the transformer was DI, and if the gas cooker had an electrical connection...

 

[steveg1957]

It would be nice if they told you whether the transformer was DI, and if the gas cooker had an electrical connection...

I am going for the gas cooker assuming there is no mains connection and is only earthed via the bonding?
The transformer would be a 'exposed conductive part' ?

Thankyou for your replies.

 

[BenStiller]

The answer is not D

 

[ban-all-sheds]

Ben - please go away, and come back when you've grown up.

 

[securespark]

I would say none of them!

 

[ban-all-sheds]

Possibly A, if it has no electrical ignition.

But if it's a free-standing cooker, supplied via a rubber hose???

 

[Qedelec]

The question is too ambiguous. There needs to more information, as indicated by the fact that this forum is served by some of the best 'time served' sparkies available and it confuses the hell out us.
So go back to your lecturer and ask him/her what the answer is and the reasoning behind the answer and perhaps we can all learn from a GURU.

p.s. "Those that can, do, those that can't teach.

 

[ban-all-sheds]

My guess is that they are trying to show the difference between extraneous-conductive-parts and exposed-conductive-parts. If they'd asked for each of a) - d) to be classified, it would be open to more questions, since (c) might be exposed, or it might not, if it's a Class II appliance.

But as the question stands, (b), (c), and (d) are immediately ruled out - they cannot be extraneous-conductive-parts as they are electrical items.

As I see it, the situation with (a) is:

[code:1]Metal gas pipe: | YES | NO |
--------------------------------------------|
Electric ignition | | |
(Class I) | Exposed | Exposed |
| | |
--------------------------------------------|
Electric ignition | | |
(Class II) | Extraneous | Neither |
| | |
--------------------------------------------|
No electric | | |
ignition | Extraneous | Neither |
| | |
--------------------------------------------|[/code:1]
Sound reasonable?

 

[Nijinski001]

Surely the answer is in the fact that it asks for 'extraneous' and in Sparks words

Extraneous conductive part. A conductive part liable to introduce a potential, generally earth potential, and not part of the electrical installation.

i.e. not part of the electrical installation rules out electric cooker and electric fire and you have to assume that the question refers to a transformer within the dwelling. Admittedly the fact of a possible electric ignition switch throws the matter into confusion but by process of elimination surely the extraneous part is the gas cooker casing?

 

[Qedelec]

There you go then Steve.
The answer is definitely (A)
Ban is never wrong.

 

[steveg1957]

Well that caused some head scratching!!

I thought there wasn't enough info on the cooker too ?
I will reveal all after next weeks lecture ........

Thanks again to all ...... with the exception of Andrew 2022

 

[ban-all-sheds]

Ban is never wrong.

If only...