Magentic Field Effect At CCTV Site

Good Morning

We are currently executing a project where we are using DAHUA DH-SDZ1020S-N fixed zoom cameras.

The project site is Industrial Aluminium production plant and has high volume of magnetic field effect throughout the area. Obviously the cameras are with housing suggested .

Is there any special protection recommended to avoid magnetic interference?

Any suggestions are appreciated


Hi Mohammed.

  1. Is it a static/low frequency magnetic field or a varying one?
  2. How strong is the field at the camera?

Typically electronic devices have a modest amount of EMI/RF shielding already, that and a stainless steel enclosure would handle modest levels of EMI. Some environments, like an MRI room though, need Faraday cage style protection.

You can get magnometer app on your phone and do some readings to find out approx how strong the field is.

Hi

1.It is not static as the site has varying magnetic field. We have 148 cameras in the field.

2.The values measured are 5.10 by -4 Tesla to 1.10 by -3 Tesla and also asked us there will be a 20% increase to be considered.

Hope this can give an idea and please advise

Mohammed, can you verify that those numbers are actually Tesla and not millaTesla? 5 Tesla is quite a strong field, for instance the magnets used in the Large Hadron Supercollider are around 8 Tesla.

Looking up what I can about the magnetic fields produced during aluminum production shows far less levels. This is off the Alcoa website about a new super smelter coming online in Saudia Arabia:

Four pot ramming machines capable of achieving high, homogenous density paste for the lining and relining of pots. The electric pot ramming machines operate at 460 V/60 Hz and are designed to handle a maximum magnetic field (100 Gauss).

100 Gauss is 10 mT. In case the field actually is multi-tesla I think you will have to get an enclosure custom made out of Mu-Metal from somewhere like Magnetic Shield. Another option is to use an MRI camera, like the one below, they can go to 7 Tesla.

Perhaps they would just sell you the enclosure.

Hi Chris

Your information is highly informative.We have tested this Dahua camera in our work shop by placing a strong magnet on top of the camera .No interfernce at all.

The rading at site will be taken and we are also going to test the camera at site.

I will post the result with the magnet reading in Gauss .

Thanks a lot to you all here given valued suggestions

Good solid grounds on all housings, conduits, raceways.

Choke Coils on all lines from the cameras , and at the point of entry to the server .

If this does not fix the problem , the use isolation coils ( optical Isolators ) between camera and line side of feed to the server .

Most quality manufacturers have in place a reference for these procedures.