Bonding the neutral is safer. Period
A floating neutral without additional expensive protection is dangerous.
Using a 'not a relay' although the mfg. calls them a 'relay adds complication, maintenance, risk and 0 benefit in a home appliance. It's actually dangerous and negligent. That is why it is not done.
NEC
NESC
NEMA
UL
etc.
In my sketch the fault will destroy both xfmrs (which apparently is not a thing lol) and possibly the load since phase has been inverted.
This has been determined by engineers over decades and not internet experts.
Thank God.
Grounding transformer connections presents its own set of challenges. This article addresses these challenges and several common configurations for control transformer grounding.
control.com
In terms of grounding, this means that the secondary output MUST be grounded, since it is another isolated part of the circuit. Any wiring failure downstream from the transformer must have a way to re-enter the circuit briefly in order to trip that circuit protection device. As with any supply, it is the Neutral wire which is bonded to ground, and this will happen just after the output of the transformer.
'Kirchhoff'
Are you saying the body Rk sees the entire fault current? It's in series?
Between all the snark
Quote:
you can say current an resistance btw.
But no fault current is
Not divided between the person (Rk) and the isolation (Risol) resistance.
they are in Series! current I will not divide if in series... (really! Lol)
Maybe you shuld go back to the basic and look at kirchosf current law.
Even in YOUR sketch the L fault I is in //!
You can't make this stuff up.
The I 'divides', (which again is not a thing, current dividers do not exist), Risol // Rk, no matter how you slice it the fault I is shared (it is the ONLY source for current).
Duke W. Schamel, P.E., LEED AP, Electrical Service Solutions, Inc.
After a national arc-flash hazard analysis project was performed at eight recently constructed parts distribution warehouse sites for a Global 100 company as part of an OSHA Voluntary Protection Program (VPP), management found the results to be somewhat
shocking.
During the data gathering process,
Electrical Service Solutions, Inc., discovered more than 35 violations of the National Electrical Code (NEC) involving improper bonding and grounding of transformers. Violations ranged from system bonding jumpers that were missing, undersized, improperly terminated, and installed in two locations to grounding electrode conductors that were either missing, undersized, improperly terminated to the electrode, and/or connected to the separately derived system in a location other than where the system bonding jumper was connected. These findings reiterate the fact that a significant amount of confusion still remains in the industry on the topic of bonding and grounding of transformers. Let’s take a closer look at the areas where most of the misconceptions arise.
The effective ground-fault current path
To understand the concept of bonding and grounding for safety, the installer must know that for normal load current, short circuit current, or ground-fault current to flow, there must be a continuous circuit or path — and a difference of potential. The 2011 NEC defines the effective ground-fault current path as “an intentionally constructed, low-impedance electrically conductive path designed and intended to carry current under ground-fault conditions from the point of a ground fault on a wiring system to the electrical supply source and that facilitates the operation of the overcurrent protective device or ground-fault detectors on high-impedance grounded systems.” An effective ground-fault current path is an essential part of the overcurrent protection system.
In summary: folks, do NOT disconnect your N from G. Under any residential circumstance. Period.
A fault will reverse polarity, elevate the other G and N, likely damage equipment, cause arcing and possible fire.
And worse, injury or death.