23 Nov
2014
23 Nov
'14
7:33 a.m.
random832 at fastmail.us wrote:
On Sat, Nov 22, 2014, at 19:33, Tothwolf wrote:
Hmm, not that effective ehy?
We also have 4 wires here, 3 phases and one neutral (Star Point)
After an Security Device, the RCD it gets split to 5 wires: 3 ?hases, the
neutral and an earth line that's connected to the metal enclosure of
connected devices. In case of an isolation failure this prevents any injury
of persons and the RCD will pop off the power if one of the phases put more
than 30mA (thats common) in the eart line.
Pictures of a singe ans a 3 phase RCD:
http://www.o-digital.com/wholesale-products/2179/2183-2/Residual-Current-De…
Regards,
Holm
--
Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe,
Freiberger Stra?e 42, 09600 Obersch?na, USt-Id: DE253710583
www.tsht.de, info at tsht.de, Fax +49 3731 74200, Mobil: 0172 8790 741
NEMA 14-30, 240V 30A, 4-wire, clothes dryers
NEMA 14-50, 240V 50A, 4-wire, electric ranges
NEMA 10-30, 240V 30A, 3-wire, clothes dryers
NEMA 10-50, 240V 50A, 3-wire, electric ranges
In the US, with systems installed before 1996, it is common to find NEMA
10 3-wire devices which lack a ground (earth) pin.
And in case anyone's wondering what we need four wires for, it's because
our 240V circuits use two opposite phases that are 120 V relative to
ground. Some appliances will use just one phase for some purposes such
as lights and timers.