Google translated version of an online version of a printed article at Israel Hayom newspaper (Original untranslated hebrew article) .

IMHO: false.
Time to time, fantastic news that something is very harmful (or beneficial) for your health are appearing. For example, mobile phones causing brain cancer some 15 years ago. And (AFAIK) the brain cancer rate hasn't increased since.

Most of your electrical devices you have at home do emit a magnetic field at the same frequency as those fuse boxes.
Electricians would be persons suffering from heart rate disorder in a remarkable way.
Strong magnetic field is used as a treatment to chronical pain etc.

I guess I know where these myths came from:

We are back in time, many years ago.
At start, there was someone with hearth problems, lets call him MisterA.
MisterA got an electronic cardio stimulator to treat his problems, a new, perfect dream device, allowing people with such diseases nearly normal life.
So after that he was able to live like anyone else, go to work, party with his friends, so really huge improvement given his condition.
Now MisterA walked somewhere with MisterB, one of his friends. And it happened, both approached such cabinet.
MisterA felt problems, so told MisterB they have to leave that place, because he has hearth problems.
So MisterB knew, his friend have hearth problems and have seen the electrical cabinet apparently worsening it.
So he concluded, the field from the cabinet is worsening the hearth problems of someone having them, so took that as an evidence the magnetic (or whatever) field affecting the hearth function. So a big article was born, how fields from these cabinets have bad effect on health, particularly hearth functionality, so how devilish the power companies are to expose public to that fields.

Well, in all that noise an important fact get lost in the very beginning: MisterA used a cardio stimulator tohelp his heart to work reasonably. And it was this cardiostimulator, what was affected by the magnetic field and malfunctioned. Well, nothing unpredictable with a sensitive electronic device.
So it was the malfunction of his stimulator, what caused MisterA problems, by far not the magnetic field.
Of course, people using these devices are instructed about this sensitivity. Of course, the immunity of such devices greatly improved over the years, so practically such malfunction should not happen with modern devices anymore, but still, as the precautions (no test could catch really all situations), wearers of such devices are adviced to be careful about any source of an electromagnetic fields potentially disturbing the equipment, just to be sure.
As MisterA was aware about the sensitive nature of his stimulator, but MisterB wasn't.
MisterB have just seen the electrical box proximity being related to the acute problems of his friend, it was sufficient to create such myth.

Yea right because we need even more scare mongering. The currently present "Danger of Death" signs from 4 sides on every electrical pole are apparently not sufficient

First thing they dont get, they judge "radiation" by "soze of box", Nevermind what is inside the box. Streetlighting group switch control point, traffic light control box, residential telecom equipment and irrigation system valves are all as harmful as 3x630A fuse boxes

Second thing. Some of the high current fuse boxes are indeed emitting electromagnetic fields of pretty high strength, which may raise concerns. But what are they exactly trying to attain with those warnings ? Would they want peeps to cross the road to avoid the box, and taking the infinity-times higher risk of death by being hit by a car ? I would suggest a better strategy. Install proper metal shielding inside the GRP boxes to block the fields, and if there are high current carrying conductors laying in loose loops inside teh boxes, tie them together where possible to improve field cancellation. And for future installations, how about making the actual boxes out of metal, like in the old days