Discussion Overview
The discussion revolves around the safety implications of touching a phase line in a 11kV/230V delta/star connected distribution transformer system where the neutral is not grounded. Participants explore the conditions under which a shock may occur and the factors influencing the current flow in such a scenario.
Discussion Character
- Technical explanation
- Debate/contested
Main Points Raised
- Some participants assert that touching one phase of the secondary line could result in a shock due to the completion of the circuit through distributed capacitance to earth.
- Others provide a counterpoint, suggesting that the shock may not be significant, depending on the capacitance and the balance of the system.
- A participant mentions that the maximum current could be estimated as 230V divided by the capacitive reactance, indicating a potential for a dangerous shock.
- There is mention of the IEEE standard recommending that the neutral be earthed with a resistor to mitigate risks associated with ungrounded systems.
- One participant shares a personal measurement experience, noting a current of around 0.3 amps in a different system, which they describe as potentially lethal.
Areas of Agreement / Disagreement
Participants express differing views on the likelihood and severity of shock when touching a phase line, indicating that multiple competing perspectives remain without a clear consensus.
Contextual Notes
The discussion highlights the dependence on system size and configuration, as well as the influence of distributed capacitance, which are not fully resolved. The implications of grounding practices are also noted but not agreed upon.