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Topic Title: Fault Loop Impedance tests in Canada
Topic Summary: Anyone worked in Canada doing periodic testing on electrical installations?
Created On: 10 October 2012 04:36 PM
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 10 October 2012 04:36 PM
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paulmcclements

Posts: 16
Joined: 13 September 2007

Hi all, a strange question but my company has a number of properties in Canada and the electrical installations are designed and maintained to the Canadian National electrical standard (CSA C22.1)by a Canadian contractor. One of my colleagues has just come back and questioned the level of maintenance that the contractor is carrying out. In particular no fault loop impedance testing is being carried out because apparently in Canada the electrical installation regs do not mention or mandate it and consequently no such equipment is able to be procured there to carry out these tests. Anyone know if this a load of cobblers?
 10 October 2012 05:23 PM
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AJJewsbury

Posts: 11272
Joined: 13 August 2003

This article: http://ecmweb.com/cee-news-arc...loop-impedance-testing seems to suggest they might be right (I presume Canadian and US codes are pretty similar).

I guess that if your supply is only 115V above earth, touch voltages for indirect contact would be about half that - so bordering on "safe" (e.g. 50V) without even without ADS.

- Andy.
 10 October 2012 06:55 PM
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jcm256

Posts: 1841
Joined: 01 April 2006

Interesting site that , the microinverters are coming, (how will BS7671 cope).

five of the most attractive markets for microinverters and power optimizers will be the United States, Canada, United Kingdom, Australia, and Japan,
 10 October 2012 07:38 PM
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rocknroll

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Joined: 03 October 2005

Anyone know if this a load of cobblers?

No it is not, in America and Canada the utility company is mandated to supply and maintain a low impedance supply to the cabinet which is situated outside the property, in the state where I have some friends the utility company do a periodic check on the supply and its impedance on a twelve monthly basis and this is recorded in the cabinet and their own records, so should anything happen the inevitable lawyers will want to view the maintenance records whilst trying to find someone to blame.

The systems in these places are based on 'increased fault current' unlike ours IEC60364 which is 'increased touch voltage', They rely heavily on RCD's (GFCI's) and as you should all know they operate at loop impedances to infinity although manufacturers state up to 10000 or 15000 ohms as an a$$ covering exercise so testing for loop impedance is bit pointless if it is periodically checked.

regards

-------------------------
"Take nothing but a picture,
leave nothing but footprints!"
-------------------------
"Oh! The drama of it all."
-------------------------
"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
-------------------------

Edited: 11 October 2012 at 08:16 AM by rocknroll
 18 October 2012 04:29 PM
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paulmcclements

Posts: 16
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Thanks for the info. The problem that we have is that it seems that there is actually no checking of anything. All maintenance is apparently retrospective so the contractor doesn't even look at the installation until something goes wrong. I've contacted someone on the Canadian equivalent of the BS7671 committee to find out exactly what they recommend for periodic maintenance.
 18 October 2012 04:54 PM
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jcm256

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 18 October 2012 08:23 PM
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rocknroll

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As I pointed out in another thread you need to forget BS7671 and all the outdated and archaic procedures you go through when looking at the way other countries and nations operate.

Although I am referring to a personal involvment in a North American State the procedures are the same throughout the whole of North America including Canada, firstly the consumer is given a low impedance maintained supply, the electrician who is licenced is bound by law to construct your installation to a code with no exceptions, unlike here where anything goes then a code inspector (these are mostly employed by their equivalent of our LA) examines your work to ensure it complies with the code, with regard to your comment on periodic testing if you carry out any extra work like a refurbishment, extension etc, or when selling the house the code inspector will visit to ensure that the codes have been adhered to.

As I pointed out when you have this level of control or in their words a legally bound 'code compliant installation' the system maintains itself so there is no need for a reactive costly unneccesary inspection regime that we have in the UK, ongoing maintenance is a different issue.

regards

-------------------------
"Take nothing but a picture,
leave nothing but footprints!"
-------------------------
"Oh! The drama of it all."
-------------------------
"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
-------------------------
 19 October 2012 05:31 PM
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weirdbeard

Posts: 1455
Joined: 26 September 2011

Originally posted by: rocknroll

As I pointed out in another thread you need to forget BS7671 and all the outdated and archaic procedures you go through when looking at the way other countries and nations operate.



Although I am referring to a personal involvment in a North American State the procedures are the same throughout the whole of North America including Canada, firstly the consumer is given a low impedance maintained supply, the electrician who is licenced is bound by law to construct your installation to a code with no exceptions, unlike here where anything goes then a code inspector (these are mostly employed by their equivalent of our LA) examines your work to ensure it complies with the code,


I must say I would be in favour of this type of situation where the electricity supplier takes a bit more responsibility and the electrician then only has more limited responsibility, though if you look on you tube and type in something like 'dangerous electrical installation' you can find there are a fair number of videos that suggest the US system is not as tightly controlled as is suggested!
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