Hi guys,
I have a case of circulating currents in a Neutral circuit.
The neutral circuit is made up of 4x500 single core cable on a 3 phase 4 wire TNC supply from a generator to a switchboard (Phase are 4x400sqmm per phase).
The 'combined' neutral curent on the N circuit was measured at 20A or...
If you needed to choose, which solution would you go for :<br> - install 2x120mm² cable per phase<br> - install 1x240mm² cable per phase<br><br>We assume of course that both are possible. (2 separate 120s can carry more than 1 240, but we'll assume here that a mutual...
In star-delta starters, there are two cables feeding the motor. Let's call them In and Out cable. In the delta configuration, the current flowing through these cables is Ib/1.732, where Ib is the current drawn through the upstream protection device.<br>To what extent is it permissible to size...
There are several short circuit calculation methods that can be used. In Europe, we have :<br>
- IEC909 : this is the standard by which LV and HV calculations should be made.<br>
- CENELEC guide R064-003 : this guide gives an alternative method, which is easier to use, but that gives...
Have any of you tried looking at IEC60092 ?!!!<br>
To what extent can you apply it 'as is'? What simplifications do you use :<br>
- what do you do in ring feed situations ?<br>
- do you systematically calculate MV and LV short circuit currents ?<br>
- do you look at the evolution, the...
When you are designing a low voltage installation, how do you estimate, or what precautions do you take to make sure (if possible), that harmonics are not going to be a problem.<br>
Harmonics from equipment like :<br>
- variable speed drives<br>
- fluo lamps<br>
- office equipment<br>...
