Busbar
Thanks for your cooperation. I followed your suggestion and talked to the lab guys. I think they will help us on what we need.
I´ll keep you informed
Busbar,
Our consultant is not an electrical engineer. But I understand his recommendation.
If you are using an equipment for, let´s say, measure the voltage on a substation maybe you won´t need an instrument with a excellent accuracy.
But if you are using it to measure small voltage deviations...
Dear fellows,
In our company we are implementing an ISO 9002 quality assurance plan. We have to calibrate all our electrical measures equipment. That is easy and we have sent them to a calibration laboratory.
Our consultant told us that we have to decide the maximum admissible error for each...
Well busbar usually we use aluminium lids on cable ladders to prevent electromagnetic induction currents on the cable ladder itself.
This is very common when we use single-core cables even if they are laid in terns. If the lid is not aluminium ( or any other non-magnetic material ) there may be...
We have to install a cable ladder in a big fuel storage compound. The cable ways are steel made and hot dip galvanized. Following the costumers demands we will only use steel armoured multiconductor cables.
The costumer also requires aluminium lids on the cable ladders to assure mechanical...
Ares,
I agree totally with you but the problem is that with conductors of 240 mm2 it´s usual practice to use single conductor cables instead of multi-conductor ones. Of course in this case, the long extension of the cables ( 150m ) is causing the current induction.
We will separate the ground...
RajT, let me clarify the situation:
The RCD it´s always the same. It´s a SIEMENS 3VF equipped with a so-called diferential module. This module accepts regulations from 10mA up to 30A with up to 200ms delay. In Portugal we normally use 300mA for common purposes and 30mA to outlets.
I have...
In one of our panels the main switch disconnector is a RCD.
It has been working fine for almost three months but suddenly it started to trip occasionally. I switch it on again and everything works perfectly for some hours,
The strange part is that I´ve seen it trip with every circuit of the...
Dear fellows,
Following your various tips I think we have discovered the reason for the high current in the earth conductor.
The step down transformer feeds the compound with two 240mm2 copper conductors in parallel for each phase; one 240mm 2 for the neutral and one 240mm2 for the earth.
Our...
Thanks a lot for your cooperation.
Let me add some information:
I have used an oscilloscope and the earth current is very distorted and so is the neutral. The phases current is an almost perfect sinusoid. What could this mean?
When I cut all the power inside the installation the earth current...
Hi everybody
I am facing a problem in a supermarket electrical installation where I´ve measured 30A in the earth conductor.
I have two diferent earths on the compound ( PE and neutral )since we use TT system in Portugal.
The supermarket has a step down transformer from 6600V down to 400 V...
