In an office, where there is a small garden, are the sockets that are supplying the office with a door to the garden *Required* to be RCD protected?
Ignoring the garden completely, is the any requirement to have RCD protection in the office at all? (Office contains the usual officey things, such as PC's lamps, franking machine, photocopiers, binding machines etc..
The reason I ask, is, the office I am working in at the moment has approximately 30 PC's It has three consumer units, all with MCB's and isolator switches.
Another issue is, the radial circuit feeding the server rack will trip when the UPS is initially turned on, so I feel the wiring may not be up to standard!
Also, the electricity meter is rated at 40A, when I measured the meter tail, the office was drawing about 55-65A - the electricity company didn't seem to worried about it until I told them their main fuse was getting quite warm - they got this changed to a 100A one, but the meter is still only 40A - should I be worried?
If there are more than around ~5 or so on one circuit, it should be wired with high integrity earthing.
Is that an MCB or RCD? UPS's (good ones at least) often draw almost no current when first switched on. They tend to wait for a bit to see if the supply is going to stay on before they start drawing their normal load or switch over their outputs. As such, they are very nice loads with regards to power up surges.
The office wiring should be getting periodic inspection/test, and it will typically say when it was last done near the supply head. The appliances in the office should be getting periodic PAT testing and have stickers say when they are next due for testing (or serial numbers which reference a database with that information).
That seems to be the norm in my experience. I had an office supply uprated to handle new air conditioning units, and the same was done, with the meter being potentially over loaded without any apparent concern (and it didn't get hot AFAICR).
Can you define this "high integrity earthing" please! Currently, it is earthed using the supply's armour, with cross-bonding to the gas and water pipes.
MCB - there aren't any RCD's, remember :-) I think it is a 16A MCB, but I will have to have a look when I am next in.
UPS's (good ones at least) often draw
It is an APC Smart-UPS 2200 RM if that helps!
Does should = it must be done at set times? is so, how often?
They have stickers - however the person who did the testing has not been on a PAT testing course - is this a requirement?
Also, how often are they required to be tested?
They will also be installing about 10KW of A/C soon - now should I worry!?
Almost ALL equuipment that does voltage concversion will either have a thwacking great iron cored transformer wih may take a HUGE current if you switch on at the wrong part of tghe cycle, or a thwacking great capacitor across the mains with just some rectifiers in series to make it DC.
It's a feature of the final branch circuit. It depends when it was wired up how it's done (regs changed). When I installed a computer room at a previous employer, it was most easily done by using a ring circuit and ensuring the two ends of the CPC went into different earth terminals in the distribution panel. More recent regs require socket outlets with two earth connections. Radial circuits usually need a second earth conductor.
I tested some ACP Smart-UPS at around 1000VA, and they drew next to nothing for first ~5 seconds.
The employer is responsible for ensuring they provide a safe workplace for their employees. It would be difficult to claim you were doing this is you never checked out the premises wiring. The inspection period depends on its state, how it is used, and how many problems are typically found during an inspection. Some employer liability insurance policies insist on annual inspections (possibly for a discount on premiums). Otherwise, in the absence of any other information, it should probably be done every 5 years.
They should be competent to do the testing or they might as well not be doing it. There's nothing in law which mentions PAT testing, but it is a way of showing compliance with 4 Acts which apply to employers. The HSE recognises C&G 2377/02 as an indication the person is competent to carry out inspection and testing of appliances. The person who does the testing and the manager responsible for ensuring it is done should take 2377/02 and 2377/01 respectively. They are each a 1 day course and exam (and you would normally do both). They are intended to be doable by non-electricians, specifically so an office can get one or two employees trained up to do appliance testing. They will need to know how to wire a plug, and understand the difference between milliohms and megohms.
That's covered in the course. It varies from daily at one extreme (e.g. for a fairground ride) through to never for some types of appliance used in some types of situation. With appropriate record keeping, you can vary the test/inspection periods if you can show a different period is justified. Something like a desktop computer which isn't moved around much and isn't used by the public might be inspected every 2 years and tested every 4 years. You might decide to write off all your desktops at 4 years old instead of testing them, as the cost of testing a 4 year old computer probably exceeds its value.
However, there's not much point testing all your appliances for correctly connected earths, etc, if you never test your premises wiring to check the sockets are actually earthed.
Whoever is designing the installation should be checking out there's a suitable electrical supply too. BTW, aircon units are best fed from dedicated supplies taken from as near the supply source as you can. Hooking them into a computer room distribution board which also supplies the computers might lead to sags in the computer supply voltage on the dist board feeder when compressors start up.
10Kw -- 43A at 230V yes you should worry!! May I suggest you need a bit of rewire, ask your aircon supplier if they want single or 3 phase. If you need a 3phase supply you need to ask for a new electrical supply, and 3 phase is not a first DIY electrical project particularly in the workplace.
Moreover, as PAT testers use high voltages and the task of testing necessarily involves working with equipment which is not yet known to be safe, having someone who has not been trained in how use a tester and how to inspect equipment before testing is itself an unsafe system of work.
Indeed. Also, if they're trained, they'll know not to do an insulation test (the high voltage test) on most IT equipment, where as if they're not trained, they will likely apply a high voltage test to IT equipment, resulting in earlier or possibly immediate failure.
Yes, make sure that the water that *WILL* inevitably piss out of the air conditioning units one day has a purely gravity operated method to get away from your IT kit ;-)
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