What is the non-auto MCCB? and what is the difference between it & the isolator?
If it is put as a main incoming to a SMDB (which in turns feeds multi DBs), & the SMDB itself is fed from an MDB (which is fed from the transformer); does the discrimination is guaranteed??
The main Low Voltage Panel (LVP) that I mean here is the panel directly connected to the transformer LV side through ACB.
In the local specifications of the project which I'm working, the panel is specified to have a thickness of minimum 2mm for its frame steel sheet body.
The contractor...
Why we put yellow/green earthing connector between parts of cable trays? does this have any relation to the bolts&nuts connecting the parts of the cable tray? (they cause a hotspot if any leakage current passes for example? or what?)
Dear all,
What are the differences in the characteristics of material between aluminium & polycarbonate?
What are the suitable applications for Al covers & what are those for polycarbonate covers in lighting fixtures?
And what about the difference in prices?
Thank you all.
Dear all,
I need to know the differences between using RMU & MV switchgear. And when to use each one.
I think in RMU:
1) Not more than one TR can be used
2) Protection relays can't be as MV switchgear.
3) Looping manueavering is not available in RMU.
Are these correct? what are the correct...
Dear all,
In a Single line diagram a dotted line is drawn between the two incomings of an MDB (one coming from transformer & the other from a generator), and written above it (ELECTRICAL AND MECHANICAL INTERLOCK).
I understand that this interlock is to execute the task of (1 out of 2), but why...
Dear all,
We used to write a comment: (All switchboards'/MCCs' components are to be from the same manufacturer), and I think this has to do with some requirement in IEC 60943 (I think which is updated by IEC 61439). Is this really a requirement in the new IEC or in any standard??
Thank you.
Dear all,
Can you help me with a PDF reference including method statements for variuos electrical works?
I need to revise those submitted by the contractor versus the good steps that shall be done in all types of electrical works (earthing, lightning, lighting fixture installation, wiring...
A distribution board (DB) in the ground floor located inside an electrical room, is fed from a Sub main distribution board (SMDB) which is located in the same room.
In the earthing schematic diagram submitted, there is no earthing cable from the earth bar installed on the wall to the earth...
Dear all,
The BMS (Building Management System) monitors all pieces of equipment within the project. A submittal for the BMS mentions that the points taken from the PFC (Power Factor Correction) is only one point "general fault". Is this correct & sufficient.
Thank you.
A query came from the contractor making the shop drawing that he can't find neither the diameter nor the height of the (earth terminal) on the design drawings (established by another company; not ours).
I didn't get what he exactly mean by "earth terminal"?? I know only the "Earth Temination...
Dear all,
I received a query on site based on design drawings. The design drawings are for CCTV site network & 11 kV power cables network (in Doha, Qatar).
1- The CCTV design drawings show a detail that mention the following:
- "Details of CCTV power and fiber optic cable trench in shared...
