Discuss conduit and trunking impedances in the Commercial Electrical Advice area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:  American Electrical Advice Forum

Hi everyone.

Can any professional here tell me where i can find the correct values of conduit or trunking
( resistance-reactance or impedance) m.Ohm per metre anywhere. Every where i have looked
IET-ECA-NICEIC give different values. One of them must be correct (i assume). I can't find a British manufacturer to find the information; you have all guessed MADE IN CHINA, so no help there!!
Any info would be a great help.
Thanks in anticipation.
 
Instyle LED Lighting Specialists UK
This official sponsor may provide discounts for members

telectrix

-
Mentor
Arms
Esteemed
the impedances of conduit and trunking will depend on the csa of the metal. it's not something you can put a value to as different manufacturers stuff will differ.
 
E

Engineer54

the impedances of conduit and trunking will depend on the csa of the metal. it's not something you can put a value to as different manufacturers stuff will differ.
If all made to a British Standard, i can't see how there could be that much difference to be honest. The metal make up may have some effect on resistance values etc. I would imagine wall thickness (CSA) would be covered within th BS specification...
 
heavy guage conduit resistance (miliohm/m) reactance (miliohm/m)
16mm 3.3 3.3
20mm 2.4 2.4
25mm 1.6 1.6
32mm 1.4 1.4

if the fault current is less than 100A, then the above values should be doubled.

the above valuies are indepenant of temperature, and can be used for design and verification.


all of the above taken from table F.11 of the Electricians Design Guide
 
  • Thread Starter Thread Starter
  • #7
Thank you for your help. I have had such different values from different sources. I will use these from now on. Thanks again.
 
im sorry about the fromatting of my post, i had ensured that the values were underneath the applicable columns, but the forum software altered it!
 
E

Engineer54

heavy guage conduit resistance (miliohm/m) reactance (miliohm/m)
16mm 3.3 3.3
Do you still use metal 16mm conduit in the UK, either in standard or heavy gage form??

I remember alarm boys using 1/2''/16mm light gage conduit, but haven't seen any used
for general building services or domestic work, since in my early training days... lol!!

They use a lot of 16mm PVC conduit in Europe (and certainly Cyprus) for embedded domestic lighting installations
and the like....
 

telectrix

-
Mentor
Arms
Esteemed
never seen 16tmm conduit in 40 years. used to use 1/2" ally tube for alarms though. in that situation, it was only there for mechanical protection.
 
E

Engineer54

never seen 16tmm conduit in 40 years. used to use 1/2" ally tube for alarms though. in that situation, it was only there for mechanical protection.
That was my point Tel... They must still be making the stuff to have a figure relating to this sized conduit. Unless it's by calculation only?? ...lol!!!

To be honest, the only 1/2'' conduit i've actually seen, was the old light gage/split seam conduit. I dont think they made it in standard or heavy gage in my time. Maybe before, but as i say i've never seen anything in this size, apart from light gage/split seam form....
 

Reply to conduit and trunking impedances in the Commercial Electrical Advice area at ElectriciansForums.net

Bulk Workwear - Clothing Suppliers for the Whole Forum Network
This official sponsor may provide discounts for members
SuperlecDirect - ElectriciansForums.net Electrical Suppliers
This official sponsor may provide discounts for members
Top Bottom