On Dec 9, 10:37 pm, John Davis wrote:
On 12/9/2011 1:37 AM, Bill Horne wrote:







On 12/8/2011 5:36 AM, David Ryeburn wrote:
This evening I checked the blog of VK1OD, which is always interesting.
The most recent posting there is "A medium priced generator set from
eBay". Worth reading.
http://www.vk1od.net/hardware/genset/index.htm
Another example of getting what you pay for.

Thanks for the link. One part caught my eye:

"Since this generator will be used with multiple appliances
of Class II, the neutral was bonded to the earth conductor
to allow the effective use of a portable RCD device."

... and I'm curious why that would be necessary. Of course, the author
is using 240 Volt, 50 Hz power, but I thought everyone kept neutral and
ground leads separate.

73,

Bill, W1AC

By code Neutral and Ground are bonded in the main service entrance box.

I have heard folks tell of portable generators where that is supposed to
"Cause Problems" however any portable generator or fixed generator
designed to supply power to a stick-build house.. Has got to be able to
deal with that.. Since many times a Generator transfer switch (Every one
I've seen) leaves neutral and ground bonded, and in fact cross
connected.. Only the "HOT" (L-1, L-2) Leads are switched.

--
Nothing adds Excitement like something that is none of your business.

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The situation that would cause the biggest problem is for the
generators neutral to ground bond becoming the return path to the
utility transformer for fault current or the neutral current should an
open neutral occur between the public utilities transformer and the
Service Disconnecting Means. In either case the wiring between the
transfer mechanism and the generator is unlikely to be capable of
safely carrying the current that would be imposed on it. Since that
wiring will usually be only large enough to carry the generators
output, rather than the Neutral current during Utility operation, if
the generator neutral is not transferred or not bonded to the
Equipment Grounding Conductor (EGC) and the Grounding Electrode
Conductors (EGC), if any, at the generator then the wiring from the
generator to the transfer mechanism would die an ignoble death while
trying to carry a current that is much too large for the size of
conductors in the circuit. With a portable generator you simply
unplug the generator from the wiring that connects it to the transfer
mechanism thus breaking the connection through the under ampacity
wiring of the generator circuit. With an optional standby generator
that will normally remain connected to the transfer mechanism it is
important to remove any bonding jumper between the generator neutral
and the frame of the generator or to have a transfer mechanism that
will transfer the neutral at the same time it transfers the ungrounded
current carrying conductors. Either arrangement will break the path
that fault or neutral current would take through the undersized
generator wiring during utility operation.

--
Tom Horne