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Yes you are right, sorry about that...

In which situation do we need to follow the communication protocol of BS EN 61850?

No I did not agree to do anything. I only told people within my organization that the sub-contractor should not be allowed to do wrong electrical design/construction practices, I have proof of this. But the subcontractor was powerful. So instead of taking action against the sub-contractor, my...

I can post details here but I have to be vague due to obvious reasons, hope you understand it. It is an engineering consulting company and they were my direct employer. The sub-contractor was performing wrong engineering (design/construction) practices and I wanted to stop it. But instead of...

If a company pushes you to do wrong electrical work which can be a risk to the safety of life, it is of course unacceptable. Does anybody know where I can complain about the company? I tried to complain to companieshouse.gov.uk , engc.org.uk , and  also  theiet.org ; but they all say that...

I understand it now. I don't need more explanation. Thanks.

Actually I know what I am doing. On the wiring diagram at page H.23 at the link below, on bottom right side it says that the control voltage between points RA & RC can either be 250VAC or 24VDC. In our case it is 250VAC...

The inverter make and model is GE VAT300.

The control voltage of VSD is 230V AC. There is no 24V DC. There are two control circuits. The first circuit is from VSD to PLC and tells the PLC that at what speed the motor is running at this time. The second circuit is from PLC to VSD and tells the VSD at what speed motor should run. The VSD...

The motor is controlled by variable-speed-drive. There is no starter. I am assuming that because it is a single motor, so control transformer is not required for the control circuit of variable-speed-drive. Please let me know comments.

The motor is for an industrial pump, and yes IEC 60204 applies in this case. The last paragraph of IEC 60204 section 9.1.1 says that control transformers are not required for machines with a single motor starter and/or a maximum of two control devices. I just need an explanation of this last...

The motor is 3-phase 400V and the control voltage is 230V. The 230V is available (L-N) without transformer. Do I still need to install a 230V(Primary)-230V(secondary) transformer?

Is it mandatory to use a control transformer for all motor control circuits? Or can we take 230V directly from the mains?

I know the basics of earthing; and how to size bonding conductors as per 544.1 and 544.2. Just trying to understand one thing: If a metal pipe is supplementary-bonded to the shower, sholuld the same metal pipe be main-bonded to the main-earthing-terminal. Thanks for help...

The distribution-board that I am working on has RCD protected receptacle circuits in bathroom, however lighting circuit in the bathroom is not RCD protected. Can supplementary bonding be still ignored?

Page 2 of ESC's earthing and bonding sheet (whose link is provided above) shows supplementary bonding of a shower. Actually the shower should already have a PE conductor (L+N+PE) ; then why does shower need supplementary-bonding? Also the shower is connected to two pipes. Are these two pipes...

where is student and learning section?

Is supplementary bonding only for showers? Does supplementary bonding only connect the shower to a nearby pipe? Or does it connect the shower to a nearby pipe as well as to the main earth terminal?

Table 54.8 gives the size of main bonding conductor with reference to neutral. However all the equipment (like water pipes, etc) that will have main bonding do not have any live (or neutral) conductor at all. So what neutral they are talking about in table 54.8?

So there are three types of conductors. Main earthing conductor, main bonding conductor, and supplementary bonding conductor. Are all of these three conductors called PE?