Hi,
May I seek some advice regarding BS 7430 requirement on resistance to earth.
I see in Annex A regarding legislation (the Electricity Supply Regulations), it states resistance to earth has to < 1 ohm. I think it's referring to TN-S system.
But how about TT system?
And how about the HV (or...
Hi,
Could anyone please advise me any formula or chart / table for sizing of fuel pipe and the exhaust chimney of a diesel generator?
The chimney needs to run vertically to tens of meters above the generator location within a building.
Thanks
PMCH
HI,
May I know if there is any rule of thumb to reserve the breaker provision for future capacitor bank and active harmonic filter in an electrical system - i.e. sizing the breaker for the future cap bank and AHF. The reason is that at the moment of design, we don't have any information about...
Hi,
May I have some advices on air flooding system. Assume I have to design an air flooding system, e.g. a pressurized raised floor, how to estimate the air pressure drop of this flooding system in order to size the external static pressure of the AHU ?
Thanks.
Hi,
I've a case where it requires an indoor air conditioned environment be maintained at 16 to 25 degC and 20% to 50% RH, for tape storage equipment. Assume the load basically is sensible load (tape storage equipment only). If just using a normal chilled water system, e.g. 7 degC supply and 12...
Hi,
Would like to seek some advices on STS. The design consultant designs with the source 1 and source 2 input to a single phase STS in different phases (e.g. S1 on L1 and S2 on L2, S1 and S2 originate from different power transformer). Assume this is incorrect / bad practice as normally S1 and...
Hi all,
May I get some advices that, normally under routine power transformer (e.g. 2MW) factory test, is the in-rush current testing essentially to be involved?
Thanks
Pgee
Hi,
I'd like to get some advices regarding NPLV testing for chillers. Per AHRI, there are testing conditions defined for NPLV. However, I'm not sure if under BSEN 14511, are there similar testing conditions defined for non-standard operating conditions?
Thanks
PGEE
Anyone have experience designing / installing a gas suppression system with a gas discharge time delay of > 30s. My understanding from NFPA is that the time delay should be sufficient for evacuation, but not definitely 30s. However, in some authorities, it's stated in their code that the time...
Hi,
If I have 2 separate UPS systems supplying a load through a downstream STS (input from the 2 UPS systems, what would happen if e.g. there is an inverter fault at UPS A (primary source to STS) - 1. UPS A transfer to the internal static bypass while STS still stick to UPS A as primary source...
