## 2 Limits, Regulations, and Methods for the EMF (electromagnetic field) Assessment Process
The EMF Directive stipulates \"exposure limits values\" (ELV, corresponding to the internal quantity, equivalent to ICNIRP's \"basic restriction\") and \"action levels\" (the external imposed field, equivalent to ICNIRP's \"reference level\"). The graph has two levels: the \"health\" ELV and corresponding \"high\" action level, and the \"sensory\" ELV and corresponding \"low\" action level Figure 1[2] presents these values at 50 Hz for electric and magnetic fields. In Romania, the maximum values allowed by the legislation (according to The General Rules for Working Safety established in 1996) are:  
For the electric field strength:  
* 10 kV/m on a full working shift;
* 30 kV/m, for a short exposure time (less than 2 h);
* The maximum exposure duration, calculated when the values of the field intensity are between 10 kV/m and 30 kV/m are calculated with the empiric relation t \(\leq\) 80/E, where t represents the duration of the recalculated working day and E is the intensity of the electric field, in kV/m. For the magnetic field induction:  
* 500 \(\mu\)T on a full working shift (some EU countries recommend 400 \(\mu\)T);
* 5 mT for short time exposures (less than 2 h);
* 25 mT for a short interval of exposure of the body extremities. ICNIRP (the International Commission on Nonionizing Radiation Protection) Guide (1998), specifies as references for public exposure to the electromagnetic field, values of 5 kV/m for the electric field and 100 uT for the magnetic field having a frequency of 50 Hz [1]. These values were also included in the corresponding Recommendation of the Council of Europe (1999). On the other hand, as a general rule, the values of the magnetic field at the points accessible to the public within the OHL corridor are much lower than the 100 uT threshold, regardless of the nominal voltage of a line. Not the same can be said about the level of the electric field, whose intensity in the vicinity of overhead lines with nominal voltages above 300 kV exceeds the threshold of 5 kV/m. These studies were the fundament of the EU EMF Directive [11]. As we can notice from these regulations, the public exposure limits are more drastic than the operational ones, however, both of them are located below the low action level. The 2013/35/EU Directive requires some different action plans at successive action levels and successive limit values for exposure. Figure 2 [2] outlines these aspects in a diagram. The main conclusions are:  
* an exposure assessment is mandatory as soon as public exposure limits are exceeded;
* the action levels could be exceeded when various provisions are put in place;
* the sensory limit values for exposure provided below can be expected if there is certain monitoring on any sensory effects that might arise;
* the health exposure limit value must not be exceeded. Figure 1: Electric and Magnetic field limits at 50 Hz. Below the high voltage lines, the electric field must be measured at a height of 1 m above the ground. If another measurement height is used (for technical reasons), it must be specified explicitly. The decision to perform measurements at a height other than 1 m can be indicated, determined by the need to reduce measurement uncertainties: it is known that the (potentially sustained) probes used to measure low-frequency electric fields are influenced by the insulating support (generally in the form of a tripod) on which they are placed [12]. Manufacturers of electric field measuring equipment, which together with the respective probe and tripod, recommend that it be \"extended\" to a certain height with the idea of sufficiently removing the probe from the support body and obtaining the specific measurement uncertainty. In the technical data sheet of the device. Because the unevenness of the electric field under a high voltage line is negligible, a single measurement point is sufficient to evaluate the level of exposure of the human body in the considered place.