Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Locked Locked
  • Replies 15 replies
  • Subscribers 39 subscribers
  • Views 4128 views
  • Users 0 members are here
Options
You may also be interested in
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Test certification & changes to supply characteristics

TaZ10101

Looking for some guidance please, I am working on a construction site with a large temporary accommodation block due to be occupied asap. Due to design issues the HV/ LV supply has been delayed, to work around this a generator will be utilised as a short term solution. 
This means testing & inspection will be completed via the genset and certs issued, when the new substation is completed the generator will be disconnected and sub-mains will be connected to the permanent LV supply. 
This raises a question regarding re-test, in my experience usually best practice would be a full re-test, but some on the project are suggesting only the sub-mains will require re-testing. 
To me this would probably come down to the designer signing the test cert and what they are prepared to accept, if only re-testing the sub-mains  I would think the final circuits Zs/ Pfc would have to be calculated as the previous test results/certs from the generator would be invalid due to the change of supply characteristics right?

So can anyone offer advice as to the options and is there anything in BS7671 regs that would be relevant to this situation, it’s also worth considering that if a EIC is issued for the generator can there be another issued for the LV supply? Is it possible to issue more than 1 EIC or  update the original or would be a condition report? 
I’ve come across this situation before and it always seems to be a contentious subject with lots of different opinions, sorry for the long winded post, but would really appreciate some professional opinions on this, thanks Pray 

Parents
  • 0

    I agree there shouldn't be a problem. Ideally the design should accommodate both the generator and grid options - the initial I&T should basically confirm that the installation meets the design (R1+R2 etc values as expected and breaking capacity of devices meets what the design called for). After the switch-over only that part of the installation actually altered for the switch-over will need a further I&T.

    If the design was initially for grid-only and was then adapted for generator (say by adding an extra RCD or three) then a bit more care is needed. but basically the same position.

       - Andy.

  • 0 in reply to AJJewsbury

    Yes , but that kind  of is the issue,  there is one original design for the HV/LV substation. As mentioned the generator is an afterthought because of delays, the principal contractor has been difficult and have reluctant to produce a separate BOD for the generator but they will now the project has stalled. Its too late to alter the original COD, so you see initial verification against the generator will not align to the network supply in any way, the designer has stipulated a complete retest,  the only way I can see as an alternative would be to calculate Zs for final circuits but management on the project view this as doing the same task twice,  there's already an additional cost to retest the submains,  it's all a bit of a mess really

Reply
  • 0 in reply to AJJewsbury

    Yes , but that kind  of is the issue,  there is one original design for the HV/LV substation. As mentioned the generator is an afterthought because of delays, the principal contractor has been difficult and have reluctant to produce a separate BOD for the generator but they will now the project has stalled. Its too late to alter the original COD, so you see initial verification against the generator will not align to the network supply in any way, the designer has stipulated a complete retest,  the only way I can see as an alternative would be to calculate Zs for final circuits but management on the project view this as doing the same task twice,  there's already an additional cost to retest the submains,  it's all a bit of a mess really

Children
No Data

Community Rules & Guidelines