ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades 400V - scary or not?

All of the free-standing stoves (ranges) that I connected up in South Africa can be supplied with 3 phase and their live terminals are marked L1, L2, L3. A busbar connects all three and is wired to the single (40-50A) phase that I have only ever seen supplied in a RSA house. The 3 phase split is used purely to balance the load although a higher phase to phase voltage would be present within the stove in these circumstances.

Interestingly, the wiring method for a free-standing differs from Province to Province as in the old Transvaal (now Gauteng, Mpumalanga, Northern and parts of Northwest) a house had, by Regulation, to be sold or rented with a stove installed. In these areas, all stoves are hard-wired to flexible conduit sheathed cables that emerge near the floor, behind the stove and under the double-pole isolator switch. Elsewhere in the country, a house comes without a stove, and in Natal where I once lived, there was a special 40A - 230V socket in the stove space. This socket was a strange round, white metal beast that protruded from the wall and faced downwards at 45 degrees and was threaded on its outer ring. It accepted a similar plug with short stubby L,N,E pins and an outer captive ring that screwed onto the socket once the pins were inserted. This plug was connected to 6sq mm cables in flexible conduit which led to the stove.

This was my first serious wiring job as a stove was never sold in Natal with the necessary cable, conduit and plug!

Don't like the idea of 415V for standard residential installations.
I have seen it occasionally, in really big houses or where there is electric storage heating with a load over 20Kw.

A lot of houses in the older parts of Inverness (pre 1930's) have a 2 phase & neutral supply. I am told this stems from the days when the supply was DC 3 wire. When conversion to 240/415V ac was carried out the existing paper/lead underground cables were re-used & many of these cables are still in service. Only 1 phase & neutral are normally taken from the service fuse to the meter, the other phase is left un-used.

Most imported stoves here also have 3 phase connections with copper links between the phases for 240V 1 ph use. I expect it enables the manufacturers to sell the same model in all EU countries & beyond.

David,

Seeing you’re a Scottish electrician, I wonder if you could answer a Scottish inquiry. My brother-in-law’s house in Glenfarg, Perthshire has an immersion heater in a closet off the landing which uses an old round-pin 15A plug as a disconnect. The house must be around 1970’s vintage. Is this normal as the set-ups I’ve known in England and South Africa are hard-wired into a double-pole isolator?

What struck me as unusual in this case was that South African immersion heaters that I am familiar with are on dedicated 30A circuits which would exceed the capacity of this connector. PaulUK said that standard UK heaters pulled about 13A. Sorry for being so far off-topic!

Interesting on the 2-phase services in Inverness. It begs another question though: Why were these houses fed with all 3 lines of the old DC service instead of the usual 2-wire tapped from 3-wire?

Are we talkng about really big homes here, which would have had very heavy loads by 1930s standards? Or was this a localized example of a 120/240 (or thereabouts) DC system instead of the usual ~240/480V?

>Stoves have the L1, L2, L3 terminals linked together.
How does that work? I learnt that electric ranges work on a 400V delta, each element fed by 2 phases.

Just remembered this one: You might like to compare the DC to 2-ph AC Inverness conversion with Ranger's post about a DC to 3-ph AC conversion in Vienna. Go here.

TR,
With the way many appliances are now sold in the same model across Europe, I've seen plenty of ranges wired for 3-phase here as well which are starpped L1-L2-L3 for use on our 1-ph residential services.

The elements are still regular 230V types, but wired on different phases to distribute the load.

Are you by any chance thinking of American 240V range elements which would be wired across the two 120V hots?

I was jsut quoting my physics teacher. I never actually checked that (we have a gas range at home, way cheaper and more effective).
Must be that way then.
I've once seen an electric range connected via simple red-grey CEE plug and receptacle at acountry fair.
Was a nice thing. They tapped off the OH service of the nearest house and ran OH cable over some trees to the big tent. One support was a long board they bound to the lavatory trailer with some insulated copper wire. They drove 2 drywall screws into the top of the board facing upwards, laid the cable between and fastened it with some wire. From the main panel they ran literally kilometers of extension cord. (Was a tent for several thousand people). I saw that work while doing some minor helper-jobs (mostly standing around and cheering up people)

On the Wye versus Delta thing on stoves:

Traditionally, our ranges have 400V rings. Thus, the range has four wires: L,L,L,PE and is hard wired. (You can also wire it L,L,PE and thus run it on 400V single-phase.)

Some new ranges are fitted with five pin (Perixlex) 3-ph plugs with a neutral. I think they are wye and can be wired to 230V too. (I should know this!) I forsee problems for many homeowners, as there are only four (1.5 mm2) wires coming out of the wall...

Today 400V only ranges have a Perilex plug where the neutral pin has been left out.

Thanks C-H, that's what I thought. All our ranges (except for the one mentioned) are hardwired to a 16A (2.5 mm2) 3ph supply.

>All our ranges (except for the one mentioned)
>are hardwired to a 16A (2.5 mm2) 3ph supply.

Why hardwire them when there are 16A Perilex plugs?

[This message has been edited by C-H (edited 11-03-2002).]