Hi there
currently doing some diversity calcs for college work and had a query about what diversity factor to apply to a 16A 3 phase commercial food holding unit.
I'm thinking that this equipment will be only used in the day time(breakfast, Lunch and Tea (what we call the evening meal- dinner...
Hi guys I’ve got a motor starter I’ve come across and looking at the electrical drawings it’s originally had 35mm tails from a 100amp fused isolator switch. This has been replaced with 25mm tri rated cable. Looking at the specs for BS 6231 I can see the conductor can take 136 amps. Motors are...
Hello,
With regards to Trimble software for bs7671 cable sizing. I understand that a three phase circuit
(No neutral) is one circuit and this can be achieved by 3 single core cables. Say for a “box” we have 5 single cables in parallel per phase (15 cables total) in Trimble for grouping purposes...
Hi All,
During my exercises on paper, we always assume the source from grid has Tension and Currentnin phase.
Today, for the first time, I was learning about Diesel Genset and noticed its plate saying 2700 MVA / 2000 MW. So basically, somehow a source has its own Power Factor (PF).
1. Can...
Hi,
We have installed 2 meters (each meter is a 3 phase meter) for sub-metering in a residential house (1 phase installation per apartment). One of the meters, after correcting installation, works fine now. The other one, in my opinion measures strange voltage values. We had since the begining...
I have a new Metrel tester and it has a .8 factor to apply to ZS. for the temperature adjustment for the cable heating up from ambient as a result of a fault.
I see .8 mentioned a lot elsewhere, is this .8 a rule of thumb derived from the equations of : rT= R20 {1 + A 20 (0-20)} =1.2 (inverse...
Where can I find specific information on pure Nickel glass woven insulated Conductors for Cable grouping factors? I want to know the derating for 60cables @1.5mm in conduit 3 Phase
Hi
This is about a design problem in an assignment.
A cable basket containing several circuits passes horizontally through an internal concrete wall (100mm) and into a ceiling void where it provides lighting throughout the building.
I'm trying to size the cables for the circuits and I'd...
Opened an IP65 JB surface mount box today (internal conservator) 2 lighting circuits including Switch cables and radial feed from last light all coming into the box. All fitted ok and all secure with Wago connectors no strain on connections.
My question is would you need to apply grouping...
I have been helping out a fellow with his lockdown assignments. One of the questions was about design. There were 60 or so high frequency electronic flurry luminaires each being 58W. The question was to work out the design current.
In the feedback on his first attempt his tutor said he had...
Hi,
Just a question from AS3000 max demand diversity table C1 for instantaneous hot water. Will it be the same diversity regardless if it is 3Ph or 1Ph or higher current rating or less?
Excuse the ignorance here but why do we have all inserts (RCD/RCBO/SPD etc) and the only thing that is constant address every make and type is a DIN rail?
Why are the sizes not universal allowing cross-brand usage, I mean a Wylex RCD should function the same as a Hager etc and yet you get some...
I'm just trying to get my head round R1+R2 calculations (predicted rather than measured). All seems very straightforward naturally, however, I'm just after clarification of something. For the 1.2 factor that is applied to adjust the resistance of conductors to operating temperature, I just...
I'm going to rewire my house, and was wondering if it's ok to have 2 shower circuits as well as cooker, sockets and lights off 1 cu, or would it be better to have 1 of the showers on a separate cu, because of the available water pressure the 2 showers are never on together.
I seem to recall there is a rating factor that can be used within an enclosure effectively uprating the current capacity of the cable. Does any one know what this is and can it be found in BS7671 or is this a rule of thumb (?) for switchboard manufacturers?
Hello
I'm not sure if this is the correct forum area to post this in, apologies if it isn't...
I've been working through some mock questions on-line, and found myself confused by this:
The measured value of loop impedance for a circuit is 0.83ohm.
If the temperature at the time of the test was...
Also just revising: trying to apply a rating factor for insulation on a cable calc. Just in theory, it's not for an actual job.
The cable will be clipped direct to joists above ceiling and is covered in >100mm thermal insulation. I cannot find the correction factor for insulation. Advice please!
hi
Looking for abit of advice?
We are quoting to replace some SWA cabling feeding various sub boards.
I have an ABB power factor correction module in place, this is feeding a control panel in the plant room, feeding motors and ventilation equipment
We need to replace the 2 x 150mm 4 core...
Hi there! I have successfully completed all parts of my coursework for level 2 and 3 2365, bar one notorious question:
A trunking run within the electrical switch-room area is to contain the following single-core thermosetting stranded cables
35 x 1.5mm2
25 x 2.5mm2
12 x 4.0mm2
10 x 10.0mm2...
Anyone know the ZS for an 1361 or BS 88-3 50A fuse. All the tables I find have n/a. I phoned the maker and was told there are no listed ZS' for a 50A and to take the difference between the next closest sizes (45A & 60), surley thats not proportional ?
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