sizing calculations for LV switchgear ?

hi V.I.Abraham ,

thanks for your reply , actually i was looking for these factors .

regards,

Thank you for your rational reply.

That was nicely put.

Please give your technical support on the following

1. In CT selection, 1A CT's are used in HT and 5A CT's are being consider for LT, why?
2. How to Select the type of enclosure form 3,3A,4,4A, 4B etc
3. Thumb rule to calculate short circuit rating for Bus bar and Equipments

1. You are wrong. 5A CTs are used where lead burden is less and 1A CTs are used where lead burden is more and that is that.

2. The selection of the type of enclosure is related to the safety, the downtime tolerability, maintainability, etc. The higher the order the better are the safety, the maintainability, etc.

3. I would not suggest any thumb rule for short circuit rating of bus bars. Rather, I would strongly suggest a thorough calculation.

Dear Vinukumar,

I am happy that you have asked me to provide technical support.Is it paid service or free? Before giving any suggestions I will request you to do some research in the net on the subject and do not expect any spoon feeding. Please read the following link . I think you may get fairly good idea about CT . You must know the CT ratio, burden and accuracy of the CT . It depends on the current to be handled to decide the ratio and level of accuracy required.

http://www.metersusa.com/Transformers/Data/CTTheory.pdf

As for Enclosures there are so many factors that have to be considered for designing an enclosure.So the factors depend on your selection. To be precise the space available to locate the panel, IP level,weather conditions and safety requirements of the locality where the panel is to be erected, material used for busbars and insulation etc.

As for current rating there is no thumb rule. It again is dependent on many parameters and requirements. It is to be calculated as per requirement including financial aspects. It should be decided depending on safety regulations and code of practice.

If you are from India, I suggest you attend to our four-day training programme on Electrical Design of Switchgear Assembly. This is conducted at our switchgear training centres at Pune, Lucknow & at Coonoor (Ooty). Please contact me at SIVAKUMARK@LNTEBG.COM for further details.

Hi,

If you are suggesting for various training programmes on LT switch gear , being conducted by L&T at their training centers, the training programmes are really good. I rate it as very good and recommend.Before attending the course one must be technically sound and have a through preliminary study of the subject ,otherwise it will be a waste of time and money. It is meant for professionals who know the subject and not for beginners or students.

Thanks Mr.Abraham, on the good feedback on our training programmes. But, I would like to add that we are also conducting 3-day training programme on Introduction To Low Voltage Switchgear to final-year EEE Students of Graduate/Diploma Programmes. Also, for freshers we have a 4-day ILTS Programme. I may be contacted for further details at: SIVAKUMARK@LNTEBG.COM