All Questions
24 questions
4
votes
5
answers
3k
views
Paintless (raw) aluminium enclosures connected to Earth: Bad practice?
I am producing a system with aluminium enclosures all connected to a central unit which is connected to Earth. All the enclosures of the system have their chassis ground connected together via cable ...
- 179
7
votes
2
answers
773
views
Should RVs electrical system be grounded to chassis?
I have an RV with both 12V and 230V systems. The 12V uses internal battery, while 230V is supplied from outside via plug. Should I connect these systems to metal frame of vehicle (minus of 12V or ...
- 1,049
7
votes
3
answers
2k
views
Dangers of floating oscilloscope
Conversation between Bob Pease and Paul Rako taken from this video, where Rako talks about modifying an oscilloscope such that it is not connected to earth:
Pease: "Have you ever tried hanging a ...
- 4,569
1
vote
1
answer
628
views
Grounding / earthing more than one places
My home earth pit is very old and it's located at the front of the house. When checking the line and neutral I am getting average 250v. When checking the Line and the Earth, I am getting 238v.
Now, I ...
0
votes
1
answer
243
views
Correct configuration for adding an earth terminal block?
I have a small motor controller test board setup like the diagram below:
A few loads such as a motor controller, and some switches are connected to the live and neutral terminal blocks for power. ...
4
votes
3
answers
12k
views
How can I check if I'm properly grounded?
I figured that if I used my trusty ol' calibrated Fluke 77 multimeter and:
Set it to Ω measurement
Measured between the ground terminal of an electrical outlet and a bare metal pipe fitting on a ...
2
votes
3
answers
1k
views
What is the potential of earth relative to mains live and neutral? [duplicate]
I'm confused about the theory of earthing in mains electrics. In particular, how the potential of "earth", the ground or literally the soil beneath my feet relates to the live and neutral ...
- 21
0
votes
2
answers
2k
views
Is earthing pointless without a residual-current device?
I don't quite understand what the situation is with the safety ground.
In theory, it evens out the voltage to zero but only if the resistance is exactly zero.
Even if the ground has only a resistance ...
6
votes
3
answers
630
views
When do I need a protective earth?
My company is developing a new handheld power tool. We are a rather inexperienced team and I am not a electrical engineer but I am concerned about the safety of our customers. We are located in ...
- 71
2
votes
4
answers
841
views
Limits to use an off-the-shelf grounded AC-DC power supply with a two-prong cable
We are selling a product using an AC-DC power supply manufactured by CUI INC (SDI24-5-U-P5 datasheet). We sold the product in a few European countries but we are currently talking with a new ...
- 346
16
votes
4
answers
5k
views
Is ground connection in home electrical system really necessary?
I know that the answer to my question is "Yes, it is!". The ground connection is needed to avoid a person touching a metallic part of faulty equipment to be electrically shocked. So the ...
- 179
3
votes
1
answer
901
views
Right way to couple DGND to Chassis ground
So we all know certain things:
DGND (and subsequently AGND) needs to be coupled to Chassis ground, or Earth at one position, at least, in a device.
The Earth is otherwise considered as a hazardous ...
- 41
0
votes
1
answer
268
views
Connect the oscilloscope to equipment with a common neutral and ground
I watched a video. At 3 minutes, the situation is shown when neutral and ground are joining. Why can this be dangerous? If we are talking about an oscilloscope, the crocodile must already be connected ...
- 23
3
votes
1
answer
516
views
Is it OK to have a connection between 0 and PE on a DC device?
I have a device meant to be used inside electrical cabinets. It has a metal casing and is powered by 24V DC. It has three power connectors: 24V, 0V and PE.
I was surprised to find out that 0V and PE ...
0
votes
1
answer
1k
views
AC to DC power supply - earth ground capacitance on DC output
I have a mains to 60v DV power supply that I’m using for a project. Needless to say it managed to give me a bit of a shock. This surprised me as it’s supposed to be floating.
With no load the power ...
- 103
1
vote
1
answer
442
views
Oscilloscope and Electrical Safety
I was reading an article in a magazine in which the following sentence is written about a circuit that generates a certain waveform on a load R (in which one of its terminals is connected to the earth ...
- 3,590
0
votes
3
answers
85
views
Electrical Standards - Earth Wire at Low Voltages?
I got a question about safety standards:
I'm designing a consumer device and I'm not sure whether I need an earth wire.
I have an AC-DC converter plug that outputs 5 V and up-to a maximum of 1 A ...
1
vote
3
answers
88
views
Connecting the Block AIM 5.0/2.0 auto-transformer to UK three-wire plug
I am not electrically very knowledgeable person. At the moment I am trying to connect a Block AIM 5.0/2.5 Auto-transformer to a piece of very sensitive medical equipment. The auto-transformer was ...
- 13
1
vote
1
answer
10k
views
Proper Chassis Grounding
I'm starting to design things that run off mains voltage and I want to be sure that I have a proper connection from my chassis to earth ground.
I've been reading a bit about proper grounding and have ...
- 501
0
votes
2
answers
1k
views
Questions about earth grounding enclosures
A text mentions about the importance of connecting the earth wire to an instrument case/enclosure as follows:
Instruments with ungrounded cases can become lethal devices in the
event of ...
- 4,385
1
vote
4
answers
6k
views
Neutral and the earth are bonded at the main panel or the substation but why is only earth wire used for safety?
Typical distribution system can be illustrated as:
Here are my premises (and assumptions):
1-) Chassis in a house must be connected to the earth, not to the neutral.
2-) The earth and the neutral ...
- 1,905
0
votes
6
answers
2k
views
Is 'grounding a desktop PC via 1MΩ resistor' unsafe when working inside the case?
Activity: maintenance (installing/replacing hardware parts, like motherboard, CPU, DIMMs, graphics cards) inside an ATX case. Goal: ESD protection and user safety.
Original question: Is 'grounding a ...
user127725
2
votes
1
answer
2k
views
Adding a resistive path between live conductors and earth - safety issues
(Note: I am in the UK so the terms 'line' and 'neutral' refer to the two live mains conductors)
I am trying to establish a list of safety issues which I should be aware of if I decide to introduce a ...
- 282
0
votes
6
answers
8k
views
Are unearthed metal cases actually unsafe?
Take a look at this picture:
It shows that if there is a fault with a device, current will flow from Live to Earth, hence you don't feel an electric shock.
However, I don't completely understand ...
- 2,776