IET - Design and production engineering

UPS Supplies

asmcgeachie — 2013-04-26T11:15:25 00

Hi All

IEEE 519 Table 10-3 states max harmonic levels (% of IL) fro Isc/IL ratio up to 50 as:
<11 harmonics - 7%
11 to 17 - 3.5%
17 to 23 - 2.5%
23 to 35 - 1%
35 - 0.5 %
TDD 8%

We are replacing a UPS, 110Vdc system.

Anyone any experience on achieving the above specification? The manufacturers are suggesting a 12 pulse rectifier with incoming filter. However some correspondence would suggest this may be difficult to a cost effective achieve.

Anyone any experience to share here?

Thanks!

App development

abdullabd — 2013-04-22T15:19:19 00

I am the rapidly being consumer at this time learning the device, reading manuals, the community and so on.mobile app development I have screened all trial programs with a computer system plus the portable application versions/VP (LOVE Aware INTERNET MARKETING from the way). I have the hint which may probably develop interesting integration choices for Aware INTERNET MARKETING along with specifically the portable version/VP.

Modeling part state during manufacture

jgdavies — 2013-04-09T12:11:36 00

Hi,
Modeling manufacture of complex parts that have many states throughout the production process, I'd like to use those states in a model.

Its common to model processes, especially software processes, that have state, but in a factory its common to pick up a processed part look at it and make some decision i.e. assign a state 'good' or 'scrapped' etc. to that part.
Parts also have an observed state as, say, process X can be observed to have been carried out, but not process Y again adding an implicit state to the part.

I'd like to be able to switch from a viewpoint of at least process, to a viewpoint of state.

SysML allows Item-flow between processes but only allows (as far as I can tell) objects i.e. 'parts' to flow, not parts in a specific state which is what happens in reality.

IDEF3 allows a process view and a state transition diagram which comes close, but every example I've seen is for state of, say, an order, and I'm not sure I can show part state in the process diagram.

Any suggestions on how to achieve this appreciated, the aim is to have an understandable-by-all viewpoint from the parts perspective and drive design of, well everything in a manufacturing system, from that when discussion between, say, IT, Operations, Automation, Processes, suppliers become lets, say 'fraught'. At such a point I'd like to be able to find the parts state, look at the next state - or transition necessary to get there, and refocus the discussion.

Reflex or transparent level gauge design calculation

bipinkaswala — 2013-04-03T11:11:29 00

Gauge glass is the most simple and common use visual level measurement device.
Generally level tube can be classified as transparent or reflex types.

A transparent tube gauge glass is attached to the bottom and top (top connection not needed in a tank open to atmosphere) of the tank that is monitored, and the height of the liquid in the tube will be equal to the height of liquid in the tank. Since the process fluid level is view directly, the transparent gauge glass is normally used with opaque fluids. Transparent gauge glasses made from tubular glass or plastic can use for service up to 450 psig and 400°F. Some of the designs of transparent and high pressure gauges are suitable for corrosive and high pressure service up to 5000psi. The glass section is usually flat to provide strength and safety.

A reflex tube gauge glass design with one side of the glass section is prism-shaped, which aid in viewing transparent fluids. The glass is one side has 90-degree angles which run lengthwise. Light rays strike the outer surface of the glass at a 90-degree angle. The light rays travel through the glass striking the inner side of the glass at a 45-degree angle. The presence or absence of liquid in the chamber determines if the light rays are refracted into the chamber or reflected back to the outer surface of the glass.

This are the working of above equipment.Now can anybudy say on what base it design and what are the design calculation i consider??

How do I become a Senior Electrical Designer?

harper1993 — 2013-04-02T05:15:36 00

hey people, just coming here for some knowledge and help from you guys. Im 20 years old and currently studying 2330 level 3.

I want to become an electrical designer, next year I will be doing HNC which I have had people tell me it is a designing qualification?
Anyway, after next year once I pass HNC I would like to increase my prospects and go on and do an honours degree, although I am not sure that designing will be included in this, I have done some research and it seems mainly electronics.. Would it be worth me taking on an honours? Would it increase my chances of getting the higher paid jobs?

Eventually I would like to be an electrical designer off shore in the oil and gas industry.

Any help is greatly appreciated
Thanks

Power per phase of a delta motor

MAXMIRA — 2013-03-28T21:41:17 00

Originally posted by: MAXMIRA

Hi all,

Can anyone help me I have been given a load schedule for a 35kw delta connected motor. The load schedule shows the 35kw spread across the three phases I.e. 11.66kw per phase. I think this is incorrect as I would put it as 35kw per phase. Can anyone tell me which is the correct method and possibly back it up with some maths. Your help would be much appreciated.

Maxmira

Robots designing and advanced programing

FrankRicharrd — 2013-03-20T14:29:53 00

Friends, can a robot be made with full feature of human physically.??
so that the robot can be implemented in any sort of works like working inside the nuclear power station and also in many difficult areas where poor human beings suffers daily. Just think, We engineers can make this world even more comfort for humans.

Integrating a new SW Development into existing Design Office

JeffAdams — 2013-03-20T13:16:41 00

Good Afternoon Folks,

this is my first posting on any IET forum - apologies if I have selected the wrong section..

I'm working for a company that designs fairly sophisticated kit used for oil exploration. The kit is designed and prototyped in the UK, and then manufactured elsewhere. It's been doing this for around 15 years. All good so far.

The kit has a lot of firmware distributed around it, and features a significant lump of central software for configuration and analysis. The software has traditionally been sourced through a partner, with no need for a local SW development function.

From this February, the software development is being transferred to a new in-house function.

Now - the company uses BS 7000-2 as a template for its processes, and is looking to get BS 9001 compliance.

The idea is to force the Software Develoment processes to fit the BS 7000-2 template.

I suspect this is the wrong approach, despite the fact that the software is being developed against a well understood set of physical principles.

Has anyone here ever tried to create embedded SW development processes that map onto BS 7000-2 with any success, or come to that, lack of success? It seems to me running a separate TickIt scheme for the department is a no-brainer, but the company does not agree!

Does anyone have any comment?

As I said - sorry if this not within the scope of this forum...

Jeff Adams

Calculations for Designing Motor Supply

niallcampbell — 2013-03-15T13:37:33 00

Hello folks,

I was wondering if anyone could help me with the following query.

Due to age/obsolescence I'm having to change an existing 7.5kW (14.5A FLC) 3phase motor out for a 15kW machine (27.8A FLC). However, I have concerns the supply cubicle may not be up to the job.

Can anyone point me in the direction of an online tool or tutorial for calculating supply requirements for motors?

Existing supply 3ph, 50Hz, 415V through 35A fuses and a 40A isolator.

Thanks for any advice, this is a new one on me and I have to admit I've not had enough exposure to design!

Ta.

Edit: I should point out that the machine is DOL not soft-start.

MTBF calculation

ebanner — 2013-03-05T15:41:17 00

Hi

I have been asked to do an MTBF calculation and have not done this before. I have a number of questions:

1. If I use MIL-STD-217F there are two update notices to this. Should I include those so the standard becomes MIL-STD-217F Notice 1 & 2.

2. I was thinking of using the parts count method. I will just add up FITS of all components on PCBs, and then inter-system components and wiring etc to get a total some of all parts and then reciprical is the MTBF.

3. If I get data from manufacturers data sheet I should know the prediction method that was used otherwise it will invalidate the result i.e. you cannot mix 217F with Telcordia 233 failure rates. It doesn't always look like manufacturers state the method used on datasheet?

Br

Edward

Testing for Reliability

AlanSellers — 2013-02-18T16:18:51 00

Hi,

I have been looking around the internet for information on testing the reliability of a particular part of a product and I have become overwhelmed by the amount of information out there.

The scenario I have is that I would like to calculate a figure for the reliability of a particular part of a product. There are 40 of this particular product in the field and I can test a small sample, e.g. 4-6, to obtain test data to use in the calculation of a reliability figure for the 40.

This raises some questions:

Given the small number of fielded units I don't think I can use normal statistical analysis because the population is too small. If that is the case how do I work out what a "significant" number of tests is to be confident in the reliability figure for the whole population?

I realise that the whole area of reliability engineering is vast so perhaps there are some useful books and websites that you could point me in the direction of?

Kind Regards,

Alan

Dimensioning a drawing

ebanner — 2013-02-05T17:28:24 00

Hi

I am working on a CAD drawing where there is several irregular shaped cutouts in a plate to pass electrical probes through.

My problem is how to dimension these shapes up. The shapes have angled edges that join fillets and also join to holes.

I was hoping I could get away with just sending a dxf (you never need to dimension up a PCB, just the very outer dimensions maybe) but the engineering company may make some parts manually and inspection need dimensions.

Can anyone help or point me at a good tutorial, most of them just seem to talk about basic dimensioning.

Distributed Generation

MasterYao — 2013-01-25T20:11:09 00

Does anyone have information or experiences regarding connection of distributed generation in US?

Electrical Schematics

notlobdivad — 2013-01-17T11:33:56 00

Hello, Sorry first time poster, not sure if this is 100% in the correcct catagory.

We are having a review of some of our major systems designs to bring them in-line with modern standards. Whilst I am aware of IEC 60617 standard which we use for the electric symbols, is there a standard for best practice in drawing layouts? I am particularly interested in DC control circuits, PLC I/O etc.

A lot of our drawings are drawn with vertical power rails and show relay logic in a ladder style diagram, however the route I have come into the job, normally I would draw a positive power rail along the top and negative along the bottom. This also appears (from the examples I have viewed) to be similar to the way Electrical CAD Packages arrange their drawings.

Whilst this appears a small and rather insignificant difference, if there is a standard that should be followed, then obviously I am keen to follow it.

David Bolton

Trends in Distribution Capacitor Controls

cbsimpson — 2013-01-10T17:22:26 00

Have any of the engineers that are a part of this group contrasted or seen the benefits/drawbacks of the operation and success of the various types of distribution capacitor controls (VAR, time, temperature, centrally radio controlled)? I am looking to do some research in this area and was interested to see if anyone had some insight concerning this topic and any previous research or findings. Mainly, I would like to hear about the experiences that engineers have had in their respective areas with these controls and the success of such implementations.

Underground cable seperate CPC

suvangrg — 2013-01-08T21:24:12 00

There is requirement to install underground cable which is 16mm2 2 core XLPE/SWA/PVC cable. This cable needed to connected from metal 3 phase distribution board ( from one of the phase) to plastic single phase distribution board. My question is do I need to run separate 16 mm2 CPC cable with the SWA cable underground? How do I terminate the other end of the cable at plastic single phase distribution board because of armour within the cable?

GPS Car alarm

Tonyita — 2012-12-28T22:15:47 00

Dear,

I would like to build a GPS car alarm to be used with an iPhone, please any tips

Regards

Antonio

from 3 phase to single phase supply

DPT — 2012-11-28T20:07:07 00

I have a small building to design. The main supply is from another building (existing) which is 3 phase and 63A protection (not sure about it). It is 7 way and 3 are spare. L1 is 96A, L2 is 54A and L3 is 84A. I am looking forward to use L2. But the new building have a load of 82.1A and probably require 100A protection. I think L2 is not big enough for the new one. Can some one fire any idea weather to get a new 3 phase line or use one of 3 spare and distribute the load across. Can existing building (3 phase 63 A) enough to take this new load?

Any one have any thought about it?

Salt-bath nitrocarburising

Kermode — 2012-11-21T12:25:22 00

Does anyone know of any UK universities doing research on this topic?

Fundamentally, it is far from being a state-of-the-art process, but there is still great potential to improve the quality management of the process. If there is any work going on in this field, it is difficult to locate.

Top priorities for research (in my opinion):
1. On-line bath composition measurement (i.e. real time)
2. Non-destructive examination of processed components

ISO fits

ebanner — 2012-11-19T18:22:07 00

Hi

I am working on a drawing which has a dowel as a location pin. Requirement is a slack fit into a 2.6mm hole but the dowel is press fitted into a hole the other side. How do you define this using ISO fits system i.e. I am thinking the shaft diameter should be 2.6c11 but then I am having trouble selecting a hole size which is press fit for c11?

Benchmarking OEE for a Newspaper Printing press

rohitkaushal — 2012-10-22T06:44:43 00

Hi guys,

I was curious to know about the OEE bench marking for news paper printing press. I am able to get reports for other presses but not specifically for News paper presses.

Help me get the reports on the Newspaper presses.

Fire detection and suppression system for emergency generator room

prakashv — 2012-10-18T21:58:27 00

Could you please advice the appropriate fire detection and suppression system for emergency generator room?
The generator room located in the basement is having 5x 1,700kVA emergency generators and engine room mounted emergency switchboard and control system arranged to start and load as per the power demand.
The room is provided with 10 supply fans, each rated for 40,000 CFM and protected with heat detectors rated for 57deg.C and automatic suppression system using form water sprinkler, reported to be approved by the local authorities.
As the generators are operated on 75% load before insulating the exhaust silencers, the detectors operated the suppression system arranged for total flooding. This spraying water above the running generators caused the generator to trip and inoperative as the winding/ panels became wet.
My questions are:
a) Is form sprinkler system suitable for generator room, especially total flooding on multiple emergency generator room?
b) Is 57Deg.C heat detector suitable, noting that summer ambient in this area cross above 50deg.C? In case the supply fans are stopped during the generators running on load or generators stopped without cooling down, the temperature will shoot above 57deg.C and activate the suppression system
c) What is the best suppression system and detections system as per IEC or BS?
Appreciate your feedback

PSCC For Design Purpose

MAXMIRA — 2012-10-16T12:07:25 00

Hi all,

I'm currently designing a 3phase distribution system and need to know what pscc to use.

The pscc has been measured across a single phase to neutral and found to be 8.1kA. In the past i have always doubled this figure as per guidance note 3 to allow for a sychronised phase fault. Therefore on this job i would have a pscc of 16.2kA.

This causes me a problem because i was planning on using schneider 60898 MCB's but they only have a breaking capacity of 10kA.

My problem is that although the site has a 3 phase supply the 60898 MCB's will be on single phase circuits so should the synchronised fault currents be used for these circuits, bare in mind they are in a 3 phase board.

Can anyone firstly confirm that i am correct to double the measured PSCC and secondly suggest a way around the problem.

Thankyou in anticipation of your much needed help.

Producing a sine wave from a square wave circuit design

devilmusic — 2012-10-12T00:53:27 00

I am currently trying to design a circuit to produce a variable frequency sine wave in the range of 150kHz to 30MHz. Is it recommended to first generate a square wave using a 555 timer in astable mode then put the square wave through an amplifier and finally into a bandpass filter to obtain the sine wave in that bandwidth?

Kindly advise,
Jon

Producing a sine wave from a square wave circuit design

devilmusic — 2012-10-12T00:53:26 00

electrical loads

justin40 — 2012-10-09T19:59:07 00

i have a small building to wire. i have added up the electrical load of the circuits allowing for diversity on the sockets and have a load of 244 amps. that load is this in real terms. the exising building is huge and is only taking 100 amps i am told. the have allowed 40 amps over 3phase to cover the additional building. im guessing some think needs to be done to the 244 amps.
helpplease

Book recommendation

SWer — 2012-09-12T19:26:18 00

Hi All. I would like to read some books on Reliability Engineering, particularly from an asset owner point of view. Specifically, when the owner only specifys the requirements for a third party and then the third party supply the parts / asset. Any recommendations would be most welcomed. Thanks

DigSilent Error Message

imanzamani — 2012-09-04T16:29:02 00

Dear All,
I am trying to do CPF (Continuation of Power flow) in Digsilent.I do the following procedure:
First of all, I select all the loads by pressing Ctrl(hold)+Left mouse button.
Next, I move cursor to one of the load and press Right mouse button.
Then, select the menu ' Excute DPL scripts' and double click on 'U_P-curve'.
Finally, I click the Execute button.
But the error that I get is as:
Dig/SI/err - --------------------------
Dig/SI/err - '/Library /DPL commands/U_P-Curve.Com Dpl':
Dig/SI/err - Object cannot be modified, no write access !
Do you know what is that error for?
Thanks

Frequency Question

sparkyaj — 2012-09-02T13:48:36 00

I wonder if anyone could help me please?

I am looking at the following symptoms on a machine:

Rotating armature which has a magnet on front face to hold down a metal die. Cylinder is getting hot and splitting cutting die equipment held on by magnetic field. Signs of resin can be seen after a few hours of use which I believe is coming out of the cylinder magnet heads, or die material? Not sure at the moment.

The armature spins at 1 revolution per second and the diameter is 203mm's.

Ultrasonic's are located at one point onto the cylinder (2 x 20KHz)

First of all, if the Cylinder being a magnet rotated - this would cause a magnetic field - how can I calculate this field??

Adding the 2 x 20KHz to this in the opposite direction, My thoughts are that EMF will be present between the two which will cause heat, and this heat along with the ultrasonic's will heat the die and magnet causing the resin to change state and become knocked out by the resin.

A simple thought process, if the supply voltage into the signal generator is too high, this could produce a higher output frequency which would then produce the above effects?

Could anyone help me calculate this please??

Thank you. Alastair

conductor design calculations for power cable

paragkulkarni — 2012-08-22T12:56:56 00

I am new here searching for calculations of aluminium conductor of 23.4 mm with 60 bobbins of 450 mm length each on 61 RST.What will be lay ratio,diameter size of different cages,no of wires required,wire elongation,%effective elongation etc?
Any one can help me?
regards
Parag Kulkarni

Calling all Manufacturing Engineers

Chunkymunky1974 — 2012-08-16T20:15:34 00

Hi All

I am new to the IET and have just embarked on the road to CEng accreditation. Whilst waiting for the paperwork to clear i thought i'd throw the proverbial doors open and see if there are any like minded individuals who are out there looking to share thoughts, stories and experiences for the good of all.

Hope to hear from somebody soon....

...anybody really

Paul

A Jack of all trades, master of the ones that noone else wants

CE Sign Off

sparkyaj — 2012-08-02T17:30:49 00

I wonder if anyone can help me please? I am working along side an mechanical engineer who has been building/repairing machines all his life in the working environment.
My question is - both he and I would like to build a machine to sell to a client.

How can we apply a CE registration to it? I appreciate all materials have to be up to standards and that workmanship must not leave the machine in a dangerous condition of any shape or form.

Any guidance would be much appreciated!

Thank you.

Electrical drawing software

JohnLindop — 2012-07-30T11:10:25 00

Hi Everyone,

I'm looking to purchase either Promis.E or ePLAN. Has anyone used either of these and how have you found them. Pros and Cons please.

Insulation Temperature Class

iochoa — 2012-07-27T11:37:53 00

What happen if a company does not specify the insulation temperature class of a electrical equipment? The supplier will design the equipment at the minimum limit?,.. in others words What are the criteria to specify a Insulation Temperature class?

Thanks,

Simulation Software

captin — 2012-07-22T22:15:14 00

Dear All,

I would like to know if some one has used IPSA+ for power system simulation as I would like to ask few questions?

Thanks

Frech machine oil over heating problem

jpichaimuthu — 2012-07-21T13:17:26 00

We have a Frech Machine DK450, we are having a few problems with this machine an "Over Heating problem".

The machine starts fine, works normally but the circulating oil is getting too hot which is over heating the machine.

I took out the heat exchanger, cleared the water path by soaking it with de-scaler which cleared the blockage of water

three weeks ago. We recently contacted Frech UK, they advised us to take out the solenoid which is on the water inlet

pipe, this did not solve our problem..

I was asked to control the flow of water through the heat exchanger, it was cooling the temperature slightly but the temperature was not constant and quickly over heats displaying a warning message on the screen "Machine is over heated".

I have checked the oil circulation motor, which is working fine, but I noticed the past few of days the motor is also over
heating.

I want to know what is the operating temperature of the relief valve and other solenoid valve, because some of the solenoid valves heats up to 58 degree C.

Thank you,
Jag

Calculating Loads for Electricity Application (UKPN)

stuartMW — 2012-07-11T09:58:45 00

Hi,

I am dealing with alot of applications to UKPN. What would be the best way of estimating loads for this application. Am i right in thinking that for an office environment, going by the BISRA rules of thumb:

Lighting 12w/m
Power 15w/m
Heating 70w/m
Cooling 125w/m

multiplied by the floor area.

Is the standard method of estimating?

Batteries Legeslation

WilliamWalker — 2012-07-05T14:35:13 00

My company manufactures a device which incorporates high energy Lithium batteries mounted in a fully encapsulated non-opening enclosure. I am a bit concerned as 2006/66/EC and BERR Batteries and Accumulators (Placing on the Market) Regulations 2008 specify that batteries MUST be made removable for disposal.

Does anyone know if it is possible to get a waiver, or similar, from this legislation? Or, who would be a good point of contact.

Nick Walker

Small scale MRP / Stock control

paulreilly — 2012-07-03T11:47:58 00

I work for an organisation that primarily does design, but also has a manufacturing operation (less than £250k per year). This is controlled by a variety of spreadsheets and card indexes, but we are considering a proper package for POs, stock control and costing for Quotation & Pricing purposes.

Any advice on simple, low-cost, low-learning-curve packages? Or should we stick with spreadsheets?

Power requirements

Sparky64 — 2012-07-02T10:16:42 00

I have been asked to calculate the power requirements for a new electrical installation in order to specify cable and MCCB sizes. This is something i have never done before and would like to know how i go about it.

I was going to add up all the Motor & transformer KW/KVA ratings and then calculate my current from this, is this correct?

Do i have to calculate the power requirements for every single device, every contactor and relay?

Any help would be greatly appreciated.

The informatioin needed for Fixed Value variable attenuators

mq — 2012-06-27T09:50:41 00

Fixed valuevariable attenuators need fixed values which were stated through decibels. His or her's software programs can include telecommunication networks, optical fiber test facility, Local Area Network(LAN) and CATV systems.
To illustrate, some -3dB variable attenuator should certainly help reduce intensity of this source by 3 dB(50%).
Fixed value variable attenuator's attenuation value shouldn't be diversified. The fiber optic attenuation might be said through dB. Typically the jogging wavelength for variable attenuators could be stated for ones rated fiber optic attenuation, considering that optical attenuation from a material fluctuates with the help of wavelength.
Fixed value variable attenuators consist from only two enormous people: In-line type and connector type. In-line type would appear that a plain fiber patch cable; it includes some fiber cable finished with the help of two connectors that you can state designs.
Connector type attenuator would appear that a bulk head fiber connector, it includes a male end and a female end. It again friends towards regular connectors of this comparable design many of these as FC, ST, SC and LC.
Sopto will provide extensive array of variable attenuators including Fixed value variable attenuators. Besides, related products including fiber media converters,Interface converter,sfp transceiver, PCIe network cards are available as well.

Controls Layout - Help!

ianreynolds — 2012-06-25T16:22:54 00

Hi All,

A layout drawing for a large heating appliance was sent to me recently for comment, as I'll be defining the wiring layout soon.

The controls include a user dual channel timer, user display, boiler control PCB, system control PLC, relays, fuses.

The wiring scheme includes 230V LV controls, 24V SELV controls, thermocouple and thermistor wiring.

My design colleagues have decreed that ALL the controls will be mounted on the front, hinged door of the appliance (opened with a tool), while all their pipes, pumps, valves et all reside permanently fixed in the appliances main chassis.

This results in approximately 54 conductors of all the wiring types mentioned above, having to be flexible aroud the hinge. A huge, heavy unsightly and difficult to build unmbilical. There is no scope for any 'nice' large diameter flexible conduit or such thing, there's no room for bulkhead fitting, etc.

Personally, I can't accept this as good design and have protested so. My decree is that only the user timer and user control should be on the door because they are designed to be.

I have to make a formal defence in a meeting this Weds 27/6.

Our core standard to meet is BS-EN 60335 (2012) which would allow such a design with loads of sleeving, earth wiring and other mitigation.

Any good arguments that support my 'bad practise' suit would be greatly appreciated!

Thanks in advance.

Transformer or UPS first?

DJUNITE — 2012-06-21T06:41:00 00

I am designing the distribution circuit for equipment to be sent to the US.
The equipment will be supported by an UPS from the US, and to get the correct voltage for my equipment I will be providing a 3-phase ste-down transformer, from 480 to 415 volts.
My question is do I step down the voltage before passing through the UPS or vice-versa?

New Build Machine Help

sparkyaj — 2012-06-07T23:03:16 00

Hello everyone. I am new to the forum and hope to learn as well as provide some valuable information and skills from here over the next few years.

I wonder if some of you could help me with some guidance please?

I am working alongside a colleague Engineer who has built an entire cutting machine which as an end result processes sheet materials, welds with ultrasonics, cuts out item and stacks in numbered quantities...

For example, you can auto feed in types of plastics and have carrier bags or gloves cut, welded and packaged out the other side.

My colleague is a very time served Engineer in his field and between us both (Engineering and Electrical) think this product could be introduced to the industry as a leading example.

Are they any options through people here at the IET that might help us forward from here please?

I very much look forward to hearing from you soon.

Many thanks, Alastair

Calibration / IPC

philium — 2012-06-07T15:24:37 00

IPC/WHMA-A-620, section 19.6 seems to say crimp tools should be calibrated every 30 days, which seems excessive. Anyone have experience of IPC?

Trunking Spacing

jdd — 2012-06-03T12:33:37 00

Hi All,

Can anyone offer any advice on trunking spacing, ie. If there are x amount of cables in it currently, how can I work out out if I can fit additional ones in. (According to regs!)

Question About Conduit Threading

jeepspark — 2012-04-18T00:40:15 00

Hi - again, I hope this is the correct forum for this query - am going to be threading 20mm galvanized steel conduit. I have been supplied with a bender and a set of imperial dies, such as 1/2", 3/4" etc. I believe these are BSP thread sizes. My question is, should I be using a 20mm die, or is that the same as 1/2" BSP? Thanks, John.

Heater Control Querie

jeepspark — 2012-04-16T09:52:40 00

Hi - (I hope I'm in the right forum for this - please advise if not) I have a specialised request from a customer for the following (for a bat house): 4 x 240W tube heaters to maintain a constant temperature of 30 degC in a small enclosed insulated space. The heaters are in close proximity to each other and there will be a temperature sensor in the centre, for logging and possible control (Pico EnviroMon system).

In order to maintain as smooth a temperature curve as possible, the customer has requested that each heater switch in/out individually, rather than all four being switched in/out together.

Can anyone suggest how this could be achieved? Is there a particular off-the-shelf 'heating control system' that would do this? Or does something have to be specially designed, perhaps using thermostats and relays?

I can supply more information as necessary. Thanks, John.

Electrical specification document required

phoenixsparky — 2012-04-08T22:31:10 00

Hi everyone, I have started work with a new employer where no other electrically skilled people work. I need to create an electrical specification to give to contractors carrying out work on site but could do with an existing one to adapt to suit. Are there any resources I could refer to?

Emergency Lighting Requirements

alexmacdonald — 2012-03-28T14:46:58 00

Do i need an emergency light in a windowless store under 60m2 which exits onto an escape route. the store has two doors at each side both with vision panels and emergency luminaires outside the doors. is borrowed emergency light through a vision panel acceptable to satisfy building regs & BS 5266?