coc point to which point

**murdock** · 02-Mar-11, 09:32 PM

i need some clarity about what point the coc covers...

from the db to a control box to the motor?

from the meter to the mains switch to the control panel to the emergency stop button on a conveyor?

all the cabling from a control panel on a machine to all the components on a machine?

to all the cables fed from a control box to all the cables supplying components all over a building....like motors...e/stops...sensors.

**Sparks** · 02-Mar-11, 09:47 PM

Now you really are stirring things up. I think we can expect a nice variety of takes on this one

**murdock** · 03-Mar-11, 07:22 AM

well lets hear them because i am in a pickle because of this on one of my projects...i was unders the impression that the coc covered from the main DB to the isolator on the machine...not the entire machine...i am now being told that if the customer requests a coc for everything including the machine...that is what you must give them...so lets hear it.

jus tto complicate things...what happens if the machine expands all over the building into different parts of the building and different levels....motors...e/stops...lights...etc

a crane for example does the coc include the cable to isolator and all the wiring on a crane?

who is responsible for the wiring on the crane.

what happens if the machine is wired up on site...for example if the control panels are installed then alll the cables to the motors etc are installed and connectedon site.

another example is central airconditioning...where there are various plant rooms and cabling is installed thru out the building to varios location.

conveyors are another one.

i look forward to the replies

**Sparks** · 03-Mar-11, 05:06 PM

First off I do not have your experience however, as you ask, I interpret the regs to read that the COC covers the installation from the entry point at the boundary of the premises up to the point of consumption. That meaning the terminals where the installation is connected to the machinery or power outlet. However, should the "integral internal" wiring be less than 500mm it would also be deemed as part of the certifiable installation. Any "appliance or machine" which is connected directly does not form part of the COC. Whether this rings true for industrial applications I will learn in time by following this thread with you.

**murdock** · 04-Mar-11, 07:51 AM

this is what i find so amazing is i have been an electrician for 30 years....run a company for just over 20 years...been involved in projects like huge shopping centres...built overhead lines...been involved in multi million rand contracts...been a master electrician for more than 20 years and i honestly cannot answer this simple question.

**Sparks** · 04-Mar-11, 07:03 PM

Not surprisingly, the authors don't know for certain themselves I am sure.

**Justloadit** · 05-Mar-11, 08:36 AM

I am no expert, however logic tells me that the COC is up to the incoming connection of the electrical machine. You can not be an expert and do a COC in the machine, as you are not trained in its operation and function, this should be left to the machine manufacturer, who in the majority of cases, if it is an industrial type of machine, would have trained qualified personnel to check the conformity and safety of the machine, and probably would not allow unqualified people to do checking and maintenance of the machine. There is no way that you as the qualified electrician, who may or may not have made the electrical connection can take responsibility for any mishaps that may occur in or on the machine. I would assume that the responsibility here either passes to the owner/user of the mcahine, or in some cases towards the manufacturer/supplier of the machine.

**murdock** · 05-Mar-11, 04:26 PM

Originally Posted by Justloadit

I am no expert, however logic tells me that the COC is up to the incoming connection of the electrical machine. You can not be an expert and do a COC in the machine, as you are not trained in its operation and function, this should be left to the machine manufacturer, who in the majority of cases, if it is an industrial type of machine, would have trained qualified personnel to check the conformity and safety of the machine, and probably would not allow unqualified people to do checking and maintenance of the machine. There is no way that you as the qualified electrician, who may or may not have made the electrical connection can take responsibility for any mishaps that may occur in or on the machine. I would assume that the responsibility here either passes to the owner/user of the mcahine, or in some cases towards the manufacturer/supplier of the machine.

i am not talking about a machine like a lathe or milling machine...i am talking about machines which are built on site and go from the basement to various levels/floors...where a company designs it... parts are built in a factory then shipped in pieces...then installed and interlinking cables are supplied and connected to the motors...sensors...e/stop buttons...sub control panels...the way i see it all these components should be covered by the oshact and sabs...so a design engineer should be involved and a commissioning sheet should be part of the installation with a complete detailed list of tests and checks required... made up by the person responsible for the design.

**Justloadit** · 05-Mar-11, 05:26 PM

I was referring to these machines that go various floors, I have been in the Star newspaper building some years back, where they print 16 complete and bound newspapers a second on each of their 5 printers. How can an electrician verify a machine if it is safe unless he has been trained on the machine. I am sure that during the installation of these machines, as you say, their technicians come out from the manufacturer to put it together to ensure that the machine is properly assembled and issue a certificate of compliance. I can not see how a standard qualified electrician has the qualifications to apply a COC on the machine. This is way out of the responsibility of the electrician. In fact no unauthorized personnel are even supposed to go near a machine of this size, can you imagine the damage that can be caused by an incident?

In any case, due to the value of the machines, I can not see the customer taking short cuts, an accident can cost millions.

**Dave A** · 05-Mar-11, 09:46 PM

Originally Posted by murdock

a commissioning sheet should be part of the installation with a complete detailed list of tests and checks required... made up by the person responsible for the design.

My thoughts have been along similar lines, steered somewhat by this discussion around more complex electrical standards issues. The first step would be to identify the applicable SANS codes as a lot more than just SANS 10142-1 is likely to apply.

The other interesting thing is what would you use for the paperwork? The standard yellow form electrical COC's test report specifically states it's for SANS 10142-1, which limits the scope somewhat.